xref: /dports/math/clp/Clp-1.17.3/CoinUtils/src/CoinOslFactorization3.cpp

/* $Id: CoinOslFactorization3.cpp 2083 2019-01-06 19:38:09Z unxusr $ */
/*
  Copyright (C) 1987, 2009, International Business Machines
  Corporation and others.  All Rights Reserved.

  This code is licensed under the terms of the Eclipse Public License (EPL).
*/
#if COIN_BIG_INDEX == 0
#include "CoinOslFactorization.hpp"
#include "CoinOslC.h"
#include "CoinFinite.hpp"
#define GO_DENSE 70
#define GO_DENSE_RATIO 1.8
int c_ekkclco(const EKKfactinfo *fact, int *hcoli,
  int *mrstrt, int *hinrow, int xnewro);

void c_ekkclcp(const int *hcol, const double *dels, const int *mrstrt,
  int *hrow, double *dels2, int *mcstrt,
  int *hincol, int itype, int nnrow, int nncol,
  int ninbas);

int c_ekkcmfc(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  EKKHlink *mwork, void *maction_void,
  int nnetas,
  int *nsingp, int *xrejctp,
  int *xnewrop, int xnewco,
  int *ncompactionsp);

int c_ekkcmfy(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  EKKHlink *mwork, void *maction_void,
  int nnetas,
  int *nsingp, int *xrejctp,
  int *xnewrop, int xnewco,
  int *ncompactionsp);

int c_ekkcmfd(EKKfactinfo *fact,
  int *mcol,
  EKKHlink *rlink, EKKHlink *clink,
  int *maction,
  int nnetas,
  int *nnentlp, int *nnentup,
  int *nsingp);
int c_ekkford(const EKKfactinfo *fact, const int *hinrow, const int *hincol,
  int *hpivro, int *hpivco,
  EKKHlink *rlink, EKKHlink *clink);
void c_ekkrowq(int *hrow, int *hcol, double *dels,
  int *mrstrt,
  const int *hinrow, int nnrow, int ninbas);
int c_ekkrwco(const EKKfactinfo *fact, double *dluval, int *hcoli, int *mrstrt, int *hinrow, int xnewro);

int c_ekkrwcs(const EKKfactinfo *fact, double *dluval, int *hcoli, int *mrstrt,
  const int *hinrow, const EKKHlink *mwork,
  int nfirst);

void c_ekkrwct(const EKKfactinfo *fact, double *dluval, int *hcoli, int *mrstrt,
  const int *hinrow, const EKKHlink *mwork,
  const EKKHlink *rlink,
  const short *msort, double *dsort,
  int nlast, int xnewro);

int c_ekkshff(EKKfactinfo *fact,
  EKKHlink *clink, EKKHlink *rlink,
  int xnewro);

void c_ekkshfv(EKKfactinfo *fact, EKKHlink *rlink, EKKHlink *clink,
  int xnewro);
int c_ekktria(EKKfactinfo *fact,
  EKKHlink *rlink,
  EKKHlink *clink,
  int *nsingp,
  int *xnewcop, int *xnewrop,
  int *nlrowtp,
  const int ninbas);
#if 0
static void c_ekkafpv(int *hentry, int *hcoli,
	     double *dluval, int *mrstrt,
	     int *hinrow, int nentry)
{
  int j;
  int nel, krs;
  int koff;
  int irow;
  int ientry;
  int * index;

  for (ientry = 0; ientry < nentry; ++ientry) {
#ifdef INTEL
    int * els_long,maxaij_long;
#endif
    double * els;
    irow = UNSHIFT_INDEX(hentry[ientry]);
    nel = hinrow[irow];
    krs = mrstrt[irow];
    index=&hcoli[krs];
    els=&dluval[krs];
#ifdef INTEL
    els_long=reinterpret_cast<int *> (els);
    maxaij_long=0;
#else
    double maxaij = 0.f;
#endif
    koff = 0;
    j=0;
    if ((nel&1)!=0) {
#ifdef INTEL
      maxaij_long = els_long[1] & 0x7fffffff;
#else
      maxaij=fabs(els[0]);
#endif
      j=1;
    }

    while (j<nel) {
#ifdef INTEL
      UNROLL_LOOP_BODY2({
	  int d_long = els_long[1+(j<<1)] & 0x7fffffff;
	  if (maxaij_long < d_long) {
	    maxaij_long = d_long;
	    koff=j;
	  }
	  j++;
	});
#else
      UNROLL_LOOP_BODY2({
	  double d = fabs(els[j]);
	  if (maxaij < d) {
	    maxaij = d;
	    koff=j;
	  }
	  j++;
	});
#endif
    }

    SWAP(int, index[koff], index[0]);
    SWAP(double, els[koff], els[0]);
  }
} /* c_ekkafpv */
#endif

/*     Uwe H. Suhl, March 1987 */
/*     This routine processes col singletons during the LU-factorization. */
/*     Return codes (checked version 1.11): */
/*	0: ok */
/*      6: pivot element too small */
/*     -43: system error at label 420 (ipivot not found) */
/*
 * This routine processes singleton columns during factorization of the
 * nucleus.  It is very similar to the first part of c_ekktria,
 * but is more complex, because we now have to maintain the length
 * lists.
 * The differences are:
 * (1) here we use the length list for length 1 rather than a queue.
 * This routine is only called if it is known that there is a singleton
 * column.
 *
 * (2) here we maintain hrowi by moving the last entry into the pivot
 * column entry; that means we don't have to search for the pivot row
 * entry like we do in c_ekktria.
 *
 * (3) here the hlink data structure is in use for the length lists,
 * so we maintain it as we shorten rows and removing columns altogether.
 *
 */
int c_ekkcsin(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,

  int *nsingp)
{
#if 1
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  //double *dvalpv = fact->kw3adr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
#endif
  const int nrow = fact->nrow;
  const double drtpiv = fact->drtpiv;

  int j, k, kc, kce, kcs, nzj;
  double pivot;
  int kipis, kipie;
  int jpivot;
#ifndef NDEBUG
  int kpivot = -1;
#else
  int kpivot = -1;
#endif

  bool small_pivot = false;

  /* next singleton column.
   * Note that when the pivot column itself was removed from the
   * list, the column in the list after it (if any) moves to the
   * head of the list.
   * Also, if any column from the pivot row was reduced to length 1,
   * then it will have been added to the list and now be in front.
   */
  for (jpivot = hpivco[1]; jpivot > 0; jpivot = hpivco[1]) {
    const int ipivot = hrowi[mcstrt[jpivot]]; /* (2) */
    assert(ipivot);
    /* The pivot row is being eliminated (3) */
    C_EKK_REMOVE_LINK(hpivro, hinrow, rlink, ipivot);

    /* Loop over nonzeros in pivot row: */
    kipis = mrstrt[ipivot];
    kipie = kipis + hinrow[ipivot] - 1;
    for (k = kipis; k <= kipie; ++k) {
      j = hcoli[k];

      /*
       * We're eliminating column jpivot,
       * so we're eliminating the row it occurs in,
       * so every column in this row is becoming one shorter.
       *
       * I don't know why we don't do the same for rejected columns.
       *
       * if xrejct is false, then no column has ever been rejected
       * and this test wouldn't have to be made.
       * However, that means this whole loop would have to be copied.
       */
      if (!(clink[j].pre > nrow)) {
        C_EKK_REMOVE_LINK(hpivco, hincol, clink, j); /* (3) */
      }
      --hincol[j];

      kcs = mcstrt[j];
      kce = kcs + hincol[j];
      for (kc = kcs; kc <= kce; ++kc) {
        if (ipivot == hrowi[kc]) {
          break;
        }
      }
      /* ASSERT !(kc>kce) */

      /* (2) */
      hrowi[kc] = hrowi[kce];
      hrowi[kce] = 0;

      if (j == jpivot) {
        /* remember the slot corresponding to the pivot column */
        kpivot = k;
      } else {
        /*
	 * We just reduced the length of the column.
	 * If we haven't eliminated all of its elements completely,
	 * then we have to put it back in its new length list.
	 *
	 * If the column was rejected, we only put it back in a length
	 * list when it has been reduced to a singleton column,
	 * because it would just be rejected again.
	 */
        nzj = hincol[j];
        if (!(nzj <= 0) && !(clink[j].pre > nrow && nzj != 1)) {
          C_EKK_ADD_LINK(hpivco, nzj, clink, j); /* (3) */
        }
      }
    }
    assert(kpivot > 0);

    /* store pivot sequence number */
    ++fact->npivots;
    rlink[ipivot].pre = -fact->npivots;
    clink[jpivot].pre = -fact->npivots;

    /* compute how much room we'll need later */
    fact->nuspike += hinrow[ipivot];

    /* check the pivot */
    pivot = dluval[kpivot];
    if (fabs(pivot) < drtpiv) {
      /* pivot element too small */
      small_pivot = true;
      rlink[ipivot].pre = -nrow - 1;
      clink[jpivot].pre = -nrow - 1;
      ++(*nsingp);
    }

    /* swap the pivoted column entry with the first entry in the row */
    dluval[kpivot] = dluval[kipis];
    dluval[kipis] = pivot;
    hcoli[kpivot] = hcoli[kipis];
    hcoli[kipis] = jpivot;
  }

  return (small_pivot);
} /* c_ekkcsin */

/*     Uwe H. Suhl, March 1987 */
/*     This routine processes row singletons during the computation of */
/*     an LU-decomposition for the nucleus. */
/*     Return codes (checked version 1.16): */
/*      -5: not enough space in row file */
/*      -6: not enough space in column file */
/*      7: pivot element too small */
/*     -52: system error at label 220 (ipivot not found) */
/*     -53: system error at label 400 (jpivot not found) */
int c_ekkrsin(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  EKKHlink *mwork, int nfirst,
  int *nsingp,
  int *xnewcop, int *xnewrop,
  int *nnentup,
  int *kmxetap, int *ncompactionsp,
  int *nnentlp)

{
#if 1
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  //double *dvalpv = fact->kw3adr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
#endif
  const int nrow = fact->nrow;
  const double drtpiv = fact->drtpiv;

  int xnewro = *xnewrop;
  int xnewco = *xnewcop;
  int kmxeta = *kmxetap;
  int nnentu = *nnentup;
  int ncompactions = *ncompactionsp;
  int nnentl = *nnentlp;

  int i, j, k, kc, kr, npr, nzi;
  double pivot;
  int kjpis, kjpie, knprs, knpre;
  double elemnt, maxaij;
  int ipivot, epivco, lstart;
#ifndef NDEBUG
  int kpivot = -1;
#else
  int kpivot = -1;
#endif
  int irtcod = 0;
  const int nnetas = fact->nnetas;

  lstart = nnetas - nnentl + 1;

  for (ipivot = hpivro[1]; ipivot > 0; ipivot = hpivro[1]) {
    const int jpivot = hcoli[mrstrt[ipivot]];

    kjpis = mcstrt[jpivot];
    kjpie = kjpis + hincol[jpivot];
    for (k = kjpis; k < kjpie; ++k) {
      i = hrowi[k];

      /*
       * We're eliminating row ipivot,
       * so we're eliminating the column it occurs in,
       * so every row in this column is becoming one shorter.
       *
       * No exception is made for rejected rows.
       */
      C_EKK_REMOVE_LINK(hpivro, hinrow, rlink, i);
    }

    /* The pivot column is being eliminated */
    /* I don't know why there is an exception for rejected columns */
    if (!(clink[jpivot].pre > nrow)) {
      C_EKK_REMOVE_LINK(hpivco, hincol, clink, jpivot);
    }

    epivco = hincol[jpivot] - 1;
    kjpie = kjpis + epivco;
    for (kc = kjpis; kc <= kjpie; ++kc) {
      if (ipivot == hrowi[kc]) {
        break;
      }
    }
    /* ASSERT !(kc>kjpie) */

    /* move the last column entry into this deleted one to keep */
    /* the entries compact */
    hrowi[kc] = hrowi[kjpie];

    hrowi[kjpie] = 0;

    /* store pivot sequence number */
    ++fact->npivots;
    rlink[ipivot].pre = -fact->npivots;
    clink[jpivot].pre = -fact->npivots;

    /* Check if row or column files have to be compressed */
    if (!(xnewro + epivco < lstart)) {
      if (!(nnentu + epivco < lstart)) {
        return (-5);
      }
      {
        int iput = c_ekkrwcs(fact, dluval, hcoli, mrstrt, hinrow, mwork, nfirst);
        kmxeta += xnewro - iput;
        xnewro = iput - 1;
        ++ncompactions;
      }
    }
    if (!(xnewco + epivco < lstart)) {
      if (!(nnentu + epivco < lstart)) {
        return (-5);
      }
      xnewco = c_ekkclco(fact, hrowi, mcstrt, hincol, xnewco);
      ++ncompactions;
    }

    /* This column has no more entries in it */
    hincol[jpivot] = 0;

    /* Perform numerical part of elimination. */
    pivot = dluval[mrstrt[ipivot]];
    if (fabs(pivot) < drtpiv) {
      irtcod = 7;
      rlink[ipivot].pre = -nrow - 1;
      clink[jpivot].pre = -nrow - 1;
      ++(*nsingp);
    }

    /* If epivco is 0, then we can treat this like a singleton column (?)*/
    if (!(epivco <= 0)) {
      ++fact->xnetal;
      mcstrt[fact->xnetal] = lstart - 1;
      hpivco[fact->xnetal] = ipivot;

      /* Loop over nonzeros in pivot column. */
      kjpis = mcstrt[jpivot];
      kjpie = kjpis + epivco;
      nnentl += epivco;
      nnentu -= epivco;
      for (kc = kjpis; kc < kjpie; ++kc) {
        npr = hrowi[kc];
        /* zero out the row entries as we go along */
        hrowi[kc] = 0;

        /* each row in the column is getting shorter */
        --hinrow[npr];

        /* find the entry in this row for the pivot column */
        knprs = mrstrt[npr];
        knpre = knprs + hinrow[npr];
        for (kr = knprs; kr <= knpre; ++kr) {
          if (jpivot == hcoli[kr])
            break;
        }
        /* ASSERT !(kr>knpre) */

        elemnt = dluval[kr];
        /* move the last pivot column entry into this one */
        /* to keep entries compact */
        dluval[kr] = dluval[knpre];
        hcoli[kr] = hcoli[knpre];

        /*
	 * c_ekkmltf put the largest entries in front, and
	 * we want to maintain that property.
	 * There is only a problem if we just pivoted out the first
	 * entry, and there is more than one entry in the list.
	 */
        if (!(kr != knprs || hinrow[npr] <= 1)) {
          maxaij = 0.f;
          for (k = knprs; k <= knpre; ++k) {
            if (!(fabs(dluval[k]) <= maxaij)) {
              maxaij = fabs(dluval[k]);
              kpivot = k;
            }
          }
          assert(kpivot > 0);
          maxaij = dluval[kpivot];
          dluval[kpivot] = dluval[knprs];
          dluval[knprs] = maxaij;

          j = hcoli[kpivot];
          hcoli[kpivot] = hcoli[knprs];
          hcoli[knprs] = j;
        }

        /* store elementary row transformation */
        --lstart;
        dluval[lstart] = -elemnt / pivot;
        hrowi[lstart] = SHIFT_INDEX(npr);

        /* Only add the row back in a length list if it isn't empty */
        nzi = hinrow[npr];
        if (!(nzi <= 0)) {
          C_EKK_ADD_LINK(hpivro, nzi, rlink, npr);
        }
      }
      ++fact->nuspike;
    }
  }

  *xnewrop = xnewro;
  *xnewcop = xnewco;
  *kmxetap = kmxeta;
  *nnentup = nnentu;
  *ncompactionsp = ncompactions;
  *nnentlp = nnentl;

  return (irtcod);
} /* c_ekkrsin */

int c_ekkfpvt(const EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  int *nsingp, int *xrejctp,
  int *xipivtp, int *xjpivtp)
{
  double zpivlu = fact->zpivlu;
#if 1
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  //double *dvalpv = fact->kw3adr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
#endif
  int i, j, k, ke, kk, ks, nz, nz1, kce, kcs, kre, krs;
  double minsze;
  int marcst, mincst, mincnt, trials, nentri;
  int jpivot = -1;
  bool rjectd;
  int ipivot;
  const int nrow = fact->nrow;
  int irtcod = 0;

  /* this used to be initialized in c_ekklfct */
  const int xtrial = 1;

  trials = 0;
  ipivot = 0;
  mincst = COIN_INT_MAX;
  mincnt = COIN_INT_MAX;
  for (nz = 2; nz <= nrow; ++nz) {
    nz1 = nz - 1;
    if (mincnt <= nz) {
      goto L900;
    }

    /* Search rows for a pivot */
    for (i = hpivro[nz]; !(i <= 0); i = rlink[i].suc) {

      ks = mrstrt[i];
      ke = ks + nz - 1;
      /* Determine magnitude of minimal acceptable element */
      minsze = fabs(dluval[ks]) * zpivlu;
      for (k = ks; k <= ke; ++k) {
        /* Consider a column only if it passes the stability test */
        if (!(fabs(dluval[k]) < minsze)) {
          j = hcoli[k];
          marcst = nz1 * hincol[j];
          if (!(marcst >= mincst)) {
            mincst = marcst;
            mincnt = hincol[j];
            ipivot = i;
            jpivot = j;
            if (mincnt <= nz + 1) {
              goto L900;
            }
          }
        }
      }
      ++trials;

      if (trials >= xtrial) {
        goto L900;
      }
    }

    /* Search columns for a pivot */
    j = hpivco[nz];
    while (!(j <= 0)) {
      /* XSEARD = XSEARD + 1 */
      rjectd = false;
      kcs = mcstrt[j];
      kce = kcs + nz - 1;
      for (k = kcs; k <= kce; ++k) {
        i = hrowi[k];
        nentri = hinrow[i];
        marcst = nz1 * nentri;
        if (!(marcst >= mincst)) {
          /* Determine magnitude of minimal acceptable element */
          minsze = fabs(dluval[mrstrt[i]]) * zpivlu;
          krs = mrstrt[i];
          kre = krs + nentri - 1;
          for (kk = krs; kk <= kre; ++kk) {
            if (hcoli[kk] == j)
              break;
          }
          /* ASSERT (kk <= kre) */

          /* perform stability test */
          if (!(fabs(dluval[kk]) < minsze)) {
            mincst = marcst;
            mincnt = nentri;
            ipivot = i;
            jpivot = j;
            rjectd = false;
            if (mincnt <= nz) {
              goto L900;
            }
          } else {
            if (ipivot == 0) {
              rjectd = true;
            }
          }
        }
      }
      ++trials;
      if (trials >= xtrial && ipivot > 0) {
        goto L900;
      }
      if (rjectd) {
        int jsuc = clink[j].suc;
        ++(*xrejctp);
        C_EKK_REMOVE_LINK(hpivco, hincol, clink, j);
        clink[j].pre = nrow + 1;
        j = jsuc;
      } else {
        j = clink[j].suc;
      }
    }
  }

  /* FLAG REJECTED ROWS (should this be columns ?) */
  for (j = 1; j <= nrow; ++j) {
    if (hinrow[j] == 0) {
      rlink[j].pre = -nrow - 1;
      ++(*nsingp);
    }
  }
  irtcod = 10;

L900:
  *xipivtp = ipivot;
  *xjpivtp = jpivot;
  return (irtcod);
} /* c_ekkfpvt */
void c_ekkprpv(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,

  int xrejct,
  int ipivot, int jpivot)
{
#if 1
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  //double *dvalpv = fact->kw3adr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
#endif
  int i, k;
  int kc;
  double pivot;
  int kipis = mrstrt[ipivot];
  int kipie = kipis + hinrow[ipivot] - 1;

#ifndef NDEBUG
  int kpivot = -1;
#else
  int kpivot = -1;
#endif
  const int nrow = fact->nrow;

  /*     Update data structures */
  {
    int kjpis = mcstrt[jpivot];
    int kjpie = kjpis + hincol[jpivot];
    for (k = kjpis; k < kjpie; ++k) {
      i = hrowi[k];
      C_EKK_REMOVE_LINK(hpivro, hinrow, rlink, i);
    }
  }

  for (k = kipis; k <= kipie; ++k) {
    int j = hcoli[k];

    if ((xrejct == 0) || !(clink[j].pre > nrow)) {
      C_EKK_REMOVE_LINK(hpivco, hincol, clink, j);
    }

    --hincol[j];
    int kcs = mcstrt[j];
    int kce = kcs + hincol[j];

    for (kc = kcs; kc < kce; kc++) {
      if (hrowi[kc] == ipivot)
        break;
    }
    assert(kc < kce || hrowi[kce] == ipivot);
    hrowi[kc] = hrowi[kce];
    hrowi[kce] = 0;
    if (j == jpivot) {
      kpivot = k;
    }
  }
  assert(kpivot > 0);

  /* Store the pivot sequence number */
  ++fact->npivots;
  rlink[ipivot].pre = -fact->npivots;
  clink[jpivot].pre = -fact->npivots;

  pivot = dluval[kpivot];
  dluval[kpivot] = dluval[kipis];
  dluval[kipis] = pivot;
  hcoli[kpivot] = hcoli[kipis];
  hcoli[kipis] = jpivot;

} /* c_ekkprpv */

/*
 * c_ekkclco is almost exactly like c_ekkrwco.
 */
int c_ekkclco(const EKKfactinfo *fact, int *hcoli, int *mrstrt, int *hinrow, int xnewro)
{
#if 0
  int *hcoli	= fact->xecadr;
  double *dluval	= fact->xeeadr;
  double *dvalpv = fact->kw3adr;
  int *mrstrt	= fact->xrsadr;
  int *hrowi	= fact->xeradr;
  int *mcstrt	= fact->xcsadr;
  int *hinrow	= fact->xrnadr;
  int *hincol	= fact->xcnadr;
  int *hpivro	= fact->krpadr;
  int *hpivco	= fact->kcpadr;
#endif
  int i, k, nz, kold;
  int kstart;
  const int nrow = fact->nrow;

  for (i = 1; i <= nrow; ++i) {
    nz = hinrow[i];
    if (0 < nz) {
      /* save the last column entry of row i in hinrow */
      /* and replace that entry with -i */
      k = mrstrt[i] + nz - 1;
      hinrow[i] = hcoli[k];
      hcoli[k] = -i;
    }
  }

  kstart = 0;
  kold = 0;
  for (k = 1; k <= xnewro; ++k) {
    if (hcoli[k] != 0) {
      ++kstart;

      /* if this is the last entry for the row... */
      if (hcoli[k] < 0) {
        /* restore the entry */
        i = -hcoli[k];
        hcoli[k] = hinrow[i];

        /* update mrstart and hinrow */
        mrstrt[i] = kold + 1;
        hinrow[i] = kstart - kold;
        kold = kstart;
      }

      hcoli[kstart] = hcoli[k];
    }
  }

  /* INSERTED INCASE CALLED FROM YTRIAN JJHF */
  mrstrt[nrow + 1] = kstart + 1;

  return (kstart);
} /* c_ekkclco */

#undef MACTION_T
#define COIN_OSL_CMFC
#define MACTION_T short int
int c_ekkcmfc(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  EKKHlink *mwork, void *maction_void,
  int nnetas,
  int *nsingp, int *xrejctp,
  int *xnewrop, int xnewco,
  int *ncompactionsp)

#include "CoinOslC.h"
#undef COIN_OSL_CMFC
#undef MACTION_T
  static int c_ekkidmx(int n, const double *dx)
{
  int ret_val;
  int i;
  double dmax;
  --dx;

  /* Function Body */

  if (n < 1) {
    return (0);
  }

  if (n == 1) {
    return (1);
  }

  ret_val = 1;
  dmax = fabs(dx[1]);
  for (i = 2; i <= n; ++i) {
    if (fabs(dx[i]) > dmax) {
      ret_val = i;
      dmax = fabs(dx[i]);
    }
  }

  return ret_val;
} /* c_ekkidmx */
/*     Return codes in IRTCOD/IRTCOD are */
/*     4: numerical problems */
/*     5: not enough space in row file */
/*     6: not enough space in column file */
int c_ekkcmfd(EKKfactinfo *fact,
  int *mcol,
  EKKHlink *rlink, EKKHlink *clink,
  int *maction,
  int nnetas,
  int *nnentlp, int *nnentup,
  int *nsingp)
{
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
  int nnentl = *nnentlp;
  int nnentu = *nnentup;
  int storeZero = fact->ndenuc;

  int mkrs[8];
  double dpivyy[8];

  /* Local variables */
  int i, j;
  double d0, dx;
  int nz, ndo, krs;
  int kend, jcol;
  int irow, iput, jrow, krxs;
  int mjcol[8];
  double pivot;
  int count;
  int ilast, isort;
  double dpivx, dsave;
  double dpivxx[8];
  double multip;
  int lstart, ndense, krlast, kcount, idense, ipivot,
    jdense, kchunk, jpivot;

  const int nrow = fact->nrow;

  int irtcod = 0;

  lstart = nnetas - nnentl + 1;

  /* put list of columns in last HROWI */
  /* fix row order once for all */
  ndense = nrow - fact->npivots;
  iput = ndense + 1;
  for (i = 1; i <= nrow; ++i) {
    if (hpivro[i] > 0) {
      irow = hpivro[i];
      for (j = 1; j <= nrow; ++j) {
        --iput;
        maction[iput] = irow;
        irow = rlink[irow].suc;
        if (irow == 0) {
          break;
        }
      }
    }
  }
  if (iput != 1) {
    ++(*nsingp);
  } else {
    /*     Use HCOLI just for last row */
    ilast = maction[1];
    krlast = mrstrt[ilast];
    /*     put list of columns in last HCOLI */
    iput = 0;
    for (i = 1; i <= nrow; ++i) {
      if (clink[i].pre >= 0) {
        hcoli[krlast + iput] = i;
        ++iput;
      }
    }
    if (iput != ndense) {
      ++(*nsingp);
    } else {
      ndo = ndense / 8;
      /*     do most */
      for (kcount = 1; kcount <= ndo; ++kcount) {
        idense = ndense;
        isort = 8;
        for (count = ndense; count >= ndense - 7; --count) {
          ipivot = maction[count];
          krs = mrstrt[ipivot];
          --isort;
          mkrs[isort] = krs;
        }
        isort = 8;
        for (count = ndense; count >= ndense - 7; --count) {
          /* Find a pivot element */
          --isort;
          ipivot = maction[count];
          krs = mkrs[isort];
          jcol = c_ekkidmx(idense, &dluval[krs]) - 1;
          pivot = dluval[krs + jcol];
          --idense;
          mcol[count] = jcol;
          mjcol[isort] = mcol[count];
          dluval[krs + jcol] = dluval[krs + idense];
          if (fabs(pivot) < fact->zeroTolerance) {
            pivot = 0.;
            dpivx = 0.;
          } else {
            dpivx = 1. / pivot;
          }
          dluval[krs + idense] = pivot;
          dpivxx[isort] = dpivx;
          for (j = isort - 1; j >= 0; --j) {
            krxs = mkrs[j];
            multip = -dluval[krxs + jcol] * dpivx;
            dluval[krxs + jcol] = dluval[krxs + idense];
            /*           for moment skip if zero */
            if (fabs(multip) > fact->zeroTolerance) {
              for (i = 0; i < idense; ++i) {
                dluval[krxs + i] += multip * dluval[krs + i];
              }
            } else {
              multip = 0.;
            }
            dluval[krxs + idense] = multip;
          }
        }
        /*       sort all U in rows already done */
        for (i = 7; i >= 0; --i) {
          /* ****     this is important bit */
          krs = mkrs[i];
          for (j = i - 1; j >= 0; --j) {
            jcol = mjcol[j];
            dsave = dluval[krs + jcol];
            dluval[krs + jcol] = dluval[krs + idense + j];
            dluval[krs + idense + j] = dsave;
          }
        }
        /*       leave IDENSE as it is */
        if (ndense <= 400) {
          for (jrow = ndense - 8; jrow >= 1; --jrow) {
            irow = maction[jrow];
            krxs = mrstrt[irow];
            for (j = 7; j >= 0; --j) {
              jcol = mjcol[j];
              dsave = dluval[krxs + jcol];
              dluval[krxs + jcol] = dluval[krxs + idense + j];
              dluval[krxs + idense + j] = dsave;
            }
            for (j = 7; j >= 0; --j) {
              krs = mkrs[j];
              jdense = idense + j;
              dpivx = dpivxx[j];
              multip = -dluval[krxs + jdense] * dpivx;
              if (fabs(multip) <= fact->zeroTolerance) {
                multip = 0.;
              }
              dpivyy[j] = multip;
              dluval[krxs + jdense] = multip;
              for (i = idense; i < jdense; ++i) {
                dluval[krxs + i] += multip * dluval[krs + i];
              }
            }
            for (i = 0; i < idense; ++i) {
              dx = dluval[krxs + i];
              d0 = dpivyy[0] * dluval[mkrs[0] + i];
              dx += dpivyy[1] * dluval[mkrs[1] + i];
              d0 += dpivyy[2] * dluval[mkrs[2] + i];
              dx += dpivyy[3] * dluval[mkrs[3] + i];
              d0 += dpivyy[4] * dluval[mkrs[4] + i];
              dx += dpivyy[5] * dluval[mkrs[5] + i];
              d0 += dpivyy[6] * dluval[mkrs[6] + i];
              dx += dpivyy[7] * dluval[mkrs[7] + i];
              dluval[krxs + i] = d0 + dx;
            }
          }
        } else {
          for (jrow = ndense - 8; jrow >= 1; --jrow) {
            irow = maction[jrow];
            krxs = mrstrt[irow];
            for (j = 7; j >= 0; --j) {
              jcol = mjcol[j];
              dsave = dluval[krxs + jcol];
              dluval[krxs + jcol] = dluval[krxs + idense + j];
              dluval[krxs + idense + j] = dsave;
            }
            for (j = 7; j >= 0; --j) {
              krs = mkrs[j];
              jdense = idense + j;
              dpivx = dpivxx[j];
              multip = -dluval[krxs + jdense] * dpivx;
              if (fabs(multip) <= fact->zeroTolerance) {
                multip = 0.;
              }
              dluval[krxs + jdense] = multip;
              for (i = idense; i < jdense; ++i) {
                dluval[krxs + i] += multip * dluval[krs + i];
              }
            }
          }
          for (kchunk = 0; kchunk < idense; kchunk += 400) {
            kend = CoinMin(idense - 1, kchunk + 399);
            for (jrow = ndense - 8; jrow >= 1; --jrow) {
              irow = maction[jrow];
              krxs = mrstrt[irow];
              for (j = 7; j >= 0; --j) {
                dpivyy[j] = dluval[krxs + idense + j];
              }
              for (i = kchunk; i <= kend; ++i) {
                dx = dluval[krxs + i];
                d0 = dpivyy[0] * dluval[mkrs[0] + i];
                dx += dpivyy[1] * dluval[mkrs[1] + i];
                d0 += dpivyy[2] * dluval[mkrs[2] + i];
                dx += dpivyy[3] * dluval[mkrs[3] + i];
                d0 += dpivyy[4] * dluval[mkrs[4] + i];
                dx += dpivyy[5] * dluval[mkrs[5] + i];
                d0 += dpivyy[6] * dluval[mkrs[6] + i];
                dx += dpivyy[7] * dluval[mkrs[7] + i];
                dluval[krxs + i] = d0 + dx;
              }
            }
          }
        }
        /*       resort all U in rows already done */
        for (i = 7; i >= 0; --i) {
          krs = mkrs[i];
          for (j = 0; j < i; ++j) {
            jcol = mjcol[j];
            dsave = dluval[krs + jcol];
            dluval[krs + jcol] = dluval[krs + idense + j];
            dluval[krs + idense + j] = dsave;
          }
        }
        ndense += -8;
      }
      idense = ndense;
      /*     do remainder */
      for (count = ndense; count >= 1; --count) {
        /*        Find a pivot element */
        ipivot = maction[count];
        krs = mrstrt[ipivot];
        jcol = c_ekkidmx(idense, &dluval[krs]) - 1;
        pivot = dluval[krs + jcol];
        --idense;
        mcol[count] = jcol;
        dluval[krs + jcol] = dluval[krs + idense];
        if (fabs(pivot) < fact->zeroTolerance) {
          dluval[krs + idense] = 0.;
        } else {
          dpivx = 1. / pivot;
          dluval[krs + idense] = pivot;
          for (jrow = idense; jrow >= 1; --jrow) {
            irow = maction[jrow];
            krxs = mrstrt[irow];
            multip = -dluval[krxs + jcol] * dpivx;
            dluval[krxs + jcol] = dluval[krxs + idense];
            /*           for moment skip if zero */
            if (fabs(multip) > fact->zeroTolerance) {
              dluval[krxs + idense] = multip;
              for (i = 0; i < idense; ++i) {
                dluval[krxs + i] += multip * dluval[krs + i];
              }
            } else {
              dluval[krxs + idense] = 0.;
            }
          }
        }
      }
      /*     now create in form for OSL */
      ndense = nrow - fact->npivots;
      idense = ndense;
      for (count = ndense; count >= 1; --count) {
        /*        Find a pivot element */
        ipivot = maction[count];
        krs = mrstrt[ipivot];
        --idense;
        jcol = mcol[count];
        jpivot = hcoli[krlast + jcol];
        ++fact->npivots;
        pivot = dluval[krs + idense];
        if (pivot == 0.) {
          hinrow[ipivot] = 0;
          rlink[ipivot].pre = -nrow - 1;
          ++(*nsingp);
          irtcod = 10;
        } else {
          rlink[ipivot].pre = -fact->npivots;
          clink[jpivot].pre = -fact->npivots;
          hincol[jpivot] = 0;
          ++fact->xnetal;
          mcstrt[fact->xnetal] = lstart - 1;
          hpivco[fact->xnetal] = ipivot;
          for (jrow = idense; jrow >= 1; --jrow) {
            irow = maction[jrow];
            krxs = mrstrt[irow];
            multip = dluval[krxs + idense];
            /*           for moment skip if zero */
            if (multip != 0. || storeZero) {
              /* Store elementary row transformation */
              ++nnentl;
              --nnentu;
              --lstart;
              dluval[lstart] = multip;
              hrowi[lstart] = SHIFT_INDEX(irow);
            }
          }
          hcoli[krlast + jcol] = hcoli[krlast + idense];
          /*         update pivot row and last row HCOLI */
          dluval[krs + idense] = dluval[krs];
          hcoli[krlast + idense] = hcoli[krlast];
          nz = 1;
          dluval[krs] = pivot;
          hcoli[krs] = jpivot;
          if (!storeZero) {
            for (i = 1; i <= idense; ++i) {
              if (fabs(dluval[krs + i]) > fact->zeroTolerance) {
                ++nz;
                hcoli[krs + nz - 1] = hcoli[krlast + i];
                dluval[krs + nz - 1] = dluval[krs + i];
              }
            }
            hinrow[ipivot] = nz;
          } else {
            for (i = 1; i <= idense; ++i) {
              ++nz;
              hcoli[krs + nz - 1] = hcoli[krlast + i];
              dluval[krs + nz - 1] = dluval[krs + i];
            }
            hinrow[ipivot] = nz;
          }
        }
      }
    }
  }

  *nnentlp = nnentl;
  *nnentup = nnentu;

  return (irtcod);
} /* c_ekkcmfd */
/* ***C_EKKCMFC */

/*
 * Generate a variant of c_ekkcmfc that uses an maction array of type
 * int rather than short.
 */
#undef MACTION_T
#define C_EKKCMFY
#define COIN_OSL_CMFC
#define MACTION_T int
int c_ekkcmfy(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  EKKHlink *mwork, void *maction_void,
  int nnetas,
  int *nsingp, int *xrejctp,
  int *xnewrop, int xnewco,
  int *ncompactionsp)

#include "CoinOslC.h"
#undef COIN_OSL_CMFC
#undef C_EKKCMFY
#undef MACTION_T
  int c_ekkford(const EKKfactinfo *fact, const int *hinrow, const int *hincol,
    int *hpivro, int *hpivco,
    EKKHlink *rlink, EKKHlink *clink)
{
  int i, iri, nzi;
  const int nrow = fact->nrow;
  int nsing = 0;

  /*     Uwe H. Suhl, August 1986 */
  /*     Builds linked lists of rows and cols of nucleus for efficient */
  /*     pivot searching. */

  memset(hpivro + 1, 0, nrow * sizeof(int));
  memset(hpivco + 1, 0, nrow * sizeof(int));
  for (i = 1; i <= nrow; ++i) {
    //hpivro[i] = 0;
    //hpivco[i] = 0;
    assert(rlink[i].suc == 0);
    assert(clink[i].suc == 0);
  }

  /*     Generate double linked list of rows having equal numbers of */
  /*     nonzeros in each row. Skip pivotal rows. */
  for (i = 1; i <= nrow; ++i) {
    if (!(rlink[i].pre < 0)) {
      nzi = hinrow[i];
      if (nzi <= 0) {
        ++nsing;
        rlink[i].pre = -nrow - 1;
      } else {
        iri = hpivro[nzi];
        hpivro[nzi] = i;
        rlink[i].suc = iri;
        rlink[i].pre = 0;
        if (iri != 0) {
          rlink[iri].pre = i;
        }
      }
    }
  }

  /*     Generate double linked list of cols having equal numbers of */
  /*     nonzeros in each col. Skip pivotal cols. */
  for (i = 1; i <= nrow; ++i) {
    if (!(clink[i].pre < 0)) {
      nzi = hincol[i];
      if (nzi <= 0) {
        ++nsing;
        clink[i].pre = -nrow - 1;
      } else {
        iri = hpivco[nzi];
        hpivco[nzi] = i;
        clink[i].suc = iri;
        clink[i].pre = 0;
        if (iri != 0) {
          clink[iri].pre = i;
        }
      }
    }
  }

  return (nsing);
} /* c_ekkford */

/*    c version of OSL from 36100 */

/*     Assumes that a basis exists in correct form */
/*     Calls Uwe's routines (approximately) */
/*     Then if OK shuffles U into column order */
/*     Return codes: */

/*     0: everything ok */
/*     1: everything ok but performance would be better if more space */
/*        would be make available */
/*     4: growth rate of element in U too big */
/*     5: not enough space in row file */
/*     6: not enough space in column file */
/*     7: pivot too small - col sing */
/*     8: pivot too small - row sing */
/*    10: matrix is singular */

/* I suspect c_ekklfct never returns 1 */
/*
 * layout of data
 *
 * dluval/hcoli:	(L^-1)B	- hole - L factors
 *
 * The L factors are written from high to low, starting from nnetas.
 * There are nnentl factors in L.  lstart the next entry to use for the
 * L factors.  Eventually, (L^-1)B turns into U.

 * The ninbas coefficients of matrix B are originally in the start of
 * dluval/hcoli.  As L transforms it, rows may have to be expanded.
 * If there is room, they are copied to the start of the hole,
 * otherwise the first part of this area is compacted, and hopefully
 * there is then room.
 * There are nnentu coefficients in (L^-1)B.
 * nnentu + nnentl >= ninbas.
 * nnentu + nnentl == ninbas if there has been no fill-in.
 * nnentu is decreased when the pivot eliminates elements
 * (in which case there is a corresponding increase in nnentl),
 * and if pivoting happens to cancel out factors (in which case
 * there is no corresponding increase in L).
 * nnentu is increased if there is fill-in (no decrease in L).
 * If nnentu + nnentl >= nnetas, then we've run out of room.
 * It is not the case that the elements of (L^-1)B are all in the
 * first nnentu positions of dluval/hcoli, but that is of course
 * the lower bound on the number of positions needed to store it.
 * nuspik is roughly the sum of the row lengths of the rows that were pivoted
 * out.  singleton rows in c_ekktria do not change nuspik, but
 * c_ekkrsin does increment it for each singleton row.
 * That is, there are nuspik elements that in the upper part of (L^-1)B,
 * and (nnentu - nuspik) elements left in B.
 */
/*
 * As part of factorization, we test candidate pivots for numerical
 * stability; if the largest element in a row/col is much larger than
 * the smallest, this generally causes problems.  To easily determine
 * what the largest element is, we ensure that it is always in front.
 * This establishes this property; later on we take steps to preserve it.
 */
static void c_ekkmltf(const EKKfactinfo *fact, double *dluval, int *hcoli,
  const int *mrstrt, const int *hinrow,
  const EKKHlink *rlink)
{
#if 0
  int *hcoli	= fact->xecadr;
  double *dluval	= fact->xeeadr;
  double *dvalpv = fact->kw3adr;
  int *mrstrt	= fact->xrsadr;
  int *hrowi	= fact->xeradr;
  int *mcstrt	= fact->xcsadr;
  int *hinrow	= fact->xrnadr;
  int *hincol	= fact->xcnadr;
  int *hpivro	= fact->krpadr;
  int *hpivco	= fact->kcpadr;
#endif
  int i, j, k;
  int koff = -1;
  const int nrow = fact->nrow;

  for (i = 1; i <= nrow; ++i) {
    /* ignore rows that have already been pivoted */
    /* if it is a singleton row, the property trivially holds */
    if (!(rlink[i].pre < 0 || hinrow[i] <= 1)) {
      const int krs = mrstrt[i];
      const int kre = krs + hinrow[i] - 1;

      double maxaij = 0.f;

      /* this assumes that at least one of the dluvals is non-zero. */
      for (k = krs; k <= kre; ++k) {
        if (!(fabs(dluval[k]) <= maxaij)) {
          maxaij = fabs(dluval[k]);
          koff = k;
        }
      }
      assert(koff > 0);
      maxaij = dluval[koff];
      j = hcoli[koff];

      dluval[koff] = dluval[krs];
      hcoli[koff] = hcoli[krs];

      dluval[krs] = maxaij;
      hcoli[krs] = j;
    }
  }
} /* c_ekkmltf */
int c_ekklfct(register EKKfactinfo *fact)
{
  const int nrow = fact->nrow;
  int ninbas = fact->xcsadr[nrow + 1] - 1;
  int ifvsol = fact->ifvsol;
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;

  EKKHlink *rlink = fact->kp1adr;
  EKKHlink *clink = fact->kp2adr;
  EKKHlink *mwork = (reinterpret_cast< EKKHlink * >(fact->kw1adr)) - 1;

  int nsing, kdnspt, xnewro, xnewco;
  int i;
  int xrejct;
  int irtcod;
  const int nnetas = fact->nnetas;

  int ncompactions;
  double save_drtpiv = fact->drtpiv;
  double save_zpivlu = fact->zpivlu;
  if (ifvsol > 0 && fact->invok < 0) {
    fact->zpivlu = CoinMin(0.9, fact->zpivlu * 10.);
    fact->drtpiv = 1.0e-8;
  }

  rlink--;
  clink--;

  /* Function Body */
  hcoli[nnetas] = 1;
  hrowi[nnetas] = 1;
  dluval[nnetas] = 0.0;
  /*     set amount of work */
  xrejct = 0;
  nsing = 0;
  kdnspt = nnetas + 1;
  fact->ndenuc = 0;
  /*     Triangularize */
  irtcod = c_ekktria(fact, rlink, clink,
    &nsing,
    &xnewco, &xnewro,
    &ncompactions, ninbas);
  fact->nnentl = ninbas - fact->nnentu;

  if (irtcod < 0) {
    /* no space or system error */
    goto L8000;
  }

  if (irtcod != 0 && fact->invok >= 0) {
    goto L8500; /* 7 or 8 - pivot too small */
  }
#if 0
  /* is this necessary ? */
  lstart = nnetas - fact->nnentl + 1;
  for (i = lstart; i <= nnetas; ++i) {
    hrowi[i] = (hcoli[i] << 3);
  }
#endif

  /* See if finished */
  if (!(fact->npivots >= nrow)) {
    int nsing1;

    /*     No - do nucleus */

    nsing1 = c_ekkford(fact, hinrow, hincol, hpivro, hpivco, rlink, clink);
    nsing += nsing1;
    if (nsing1 != 0 && fact->invok >= 0) {
      irtcod = 7;
      goto L8500;
    }
    c_ekkmltf(fact, dluval, hcoli, mrstrt, hinrow, rlink);

    {
      bool callcmfy = false;

      if (nrow > 32767) {
        int count = 0;
        for (i = 1; i <= nrow; ++i) {
          count = CoinMax(count, hinrow[i]);
        }
        if (count + nrow - fact->npivots > 32767) {
          /* will have to use I*4 version of CMFC */
          /* no changes to pointer params */
          callcmfy = true;
        }
      }

      irtcod = (callcmfy ? c_ekkcmfy : c_ekkcmfc)(fact,
        rlink, clink,
        mwork, &mwork[nrow + 1],
        nnetas,
        &nsing, &xrejct,
        &xnewro, xnewco,
        &ncompactions);

      /* irtcod one of 0,-5,7,10 */
    }

    if (irtcod < 0) {
      goto L8000;
    }
    kdnspt = nnetas - fact->nnentl;
  }

  /*     return if error */
  if (nsing > 0 || irtcod == 10) {
    irtcod = 99;
  }
  /* irtcod one of 0,7,99 */

  if (irtcod != 0) {
    goto L8500;
  }
  ++fact->xnetal;
  mcstrt[fact->xnetal] = nnetas - fact->nnentl;

  /* give message if tight on memory */
  if (ncompactions > 2) {
    if (1) {
      int etasize = CoinMax(4 * fact->nnentu + (nnetas - fact->nnentl) + 1000, fact->eta_size);
      fact->eta_size = CoinMin(static_cast< int >(1.2 * fact->eta_size), etasize);
      if (fact->maxNNetas > 0 && fact->eta_size > fact->maxNNetas) {
        fact->eta_size = fact->maxNNetas;
      }
    } /* endif */
  }
  /*       Shuffle U and multiply L by 8 (if assembler) */
  {
    int jrtcod = c_ekkshff(fact, clink, rlink,
      xnewro);

    /* nR_etas is the number of R transforms;
     * it is incremented only in c_ekketsj.
     */
    fact->nR_etas = 0;
    /*fact->R_etas_start = mcstrt+nrow+fact->nnentl+3;*/
    fact->R_etas_start[1] = /*kdnspt - 1*/ 0; /* magic */
    fact->R_etas_index = &fact->xeradr[kdnspt - 1];
    fact->R_etas_element = &fact->xeeadr[kdnspt - 1];

    if (jrtcod != 0) {
      irtcod = jrtcod;
      /* irtcod == 2 */
    }
  }
  goto L8500;

  /* Fatal error */
L8000:

  if (1) {
    if (fact->maxNNetas != fact->eta_size && nnetas) {
      /* return and get more space */

      /* double eta_size, unless that exceeds max (if there is one) */
      fact->eta_size = fact->eta_size << 1;
      if (fact->maxNNetas > 0 && fact->eta_size > fact->maxNNetas) {
        fact->eta_size = fact->maxNNetas;
      }
      return (5);
    }
  }
  /*c_ekkmesg_no_i1(121, -irtcod);*/
  irtcod = 3;

L8500:
  /* restore pivot tolerance */
  fact->drtpiv = save_drtpiv;
  fact->zpivlu = save_zpivlu;
#ifndef NDEBUG
  if (fact->rows_ok) {
    int *hinrow = fact->xrnadr;
    if (!fact->xe2adr) {
      for (int i = 1; i <= fact->nrow; i++) {
        assert(hinrow[i] >= 0 && hinrow[i] <= fact->nrow);
      }
    }
  }
#endif
  return (irtcod);
} /* c_ekklfct */

/*
  summary of return codes

  c_ekktria:
  7 small pivot
  -5 no memory

  c_ekkcsin:
  returns true if small pivot

  c_ekkrsin:
  -5 no memory
  7 small pivot

  c_ekkfpvt:
  10: no pivots found (singular)

  c_ekkcmfd:
  10: zero pivot (not just small)

  c_ekkcmfc:
  -5:  no memory
  any non-zero code from c_ekkcsin, c_ekkrsin, c_ekkfpvt, c_ekkprpv, c_ekkcmfd

  c_ekkshff:
  2:  singular

  c_ekklfct:
  any positive code from c_ekktria, c_ekkcmfc, c_ekkshff (2,7,10)
  *except* 10, which is changed to 99.
  all negative return codes are changed to 5 or 3
  (5 == ran out of memory but could get more,
  3 == ran out of memory, no luck)
  so:  2,3,5,7,99

  c_ekklfct1:
  1: c_ekksmem_invert failed
  2: c_ekkslcf/c_ekkslct ran out of room
  any return code from c_ekklfct, except 2 and 5
*/

void c_ekkrowq(int *hrow, int *hcol, double *dels,
  int *mrstrt,
  const int *hinrow, int nnrow, int ninbas)
{
  int i, k, iak, jak;
  double daik;
  int iloc;
  double dsave;
  int isave, jsave;

  /* Order matrix rowwise using MRSTRT, DELS, HCOL */

  k = 1;
  /* POSITION AFTER END OF ROW */
  for (i = 1; i <= nnrow; ++i) {
    k += hinrow[i];
    mrstrt[i] = k;
  }

  for (k = ninbas; k >= 1; --k) {
    iak = hrow[k];
    if (iak != 0) {
      daik = dels[k];
      jak = hcol[k];
      hrow[k] = 0;
      while (1) {
        --mrstrt[iak];

        iloc = mrstrt[iak];

        dsave = dels[iloc];
        isave = hrow[iloc];
        jsave = hcol[iloc];
        dels[iloc] = daik;
        hrow[iloc] = 0;
        hcol[iloc] = jak;

        if (isave == 0)
          break;
        daik = dsave;
        iak = isave;
        jak = jsave;
      }
    }
  }
} /* c_ekkrowq */

int c_ekkrwco(const EKKfactinfo *fact, double *dluval,
  int *hcoli, int *mrstrt, int *hinrow, int xnewro)
{
  int i, k, nz, kold;
  int kstart;
  const int nrow = fact->nrow;

  for (i = 1; i <= nrow; ++i) {
    nz = hinrow[i];
    if (0 < nz) {
      /* save the last column entry of row i in hinrow */
      /* and replace that entry with -i */
      k = mrstrt[i] + nz - 1;
      hinrow[i] = hcoli[k];
      hcoli[k] = -i;
    }
  }

  kstart = 0;
  kold = 0;
  for (k = 1; k <= xnewro; ++k) {
    if (hcoli[k] != 0) {
      ++kstart;

      /* if this is the last entry for the row... */
      if (hcoli[k] < 0) {
        /* restore the entry */
        i = -hcoli[k];
        hcoli[k] = hinrow[i];

        /* update mrstart and hinrow */
        /* ACTUALLY, hinrow should already be accurate */
        mrstrt[i] = kold + 1;
        hinrow[i] = kstart - kold;
        kold = kstart;
      }

      /* move the entry */
      dluval[kstart] = dluval[k];
      hcoli[kstart] = hcoli[k];
    }
  }

  return (kstart);
} /* c_ekkrwco */

int c_ekkrwcs(const EKKfactinfo *fact, double *dluval, int *hcoli, int *mrstrt,
  const int *hinrow, const EKKHlink *mwork,
  int nfirst)
{
#if 0
  int *hcoli	= fact->xecadr;
  double *dluval	= fact->xeeadr;
  double *dvalpv = fact->kw3adr;
  int *mrstrt	= fact->xrsadr;
  int *hrowi	= fact->xeradr;
  int *mcstrt	= fact->xcsadr;
  int *hinrow	= fact->xrnadr;
  int *hincol	= fact->xcnadr;
  int *hpivro	= fact->krpadr;
  int *hpivco	= fact->kcpadr;
#endif
  int i, k, k1, k2, nz;
  int irow, iput;
  const int nrow = fact->nrow;

  /*     Compress row file */

  iput = 1;
  irow = nfirst;
  for (i = 1; i <= nrow; ++i) {
    nz = hinrow[irow];
    k1 = mrstrt[irow];
    if (k1 != iput) {
      mrstrt[irow] = iput;
      k2 = k1 + nz - 1;
      for (k = k1; k <= k2; ++k) {
        dluval[iput] = dluval[k];
        hcoli[iput] = hcoli[k];
        ++iput;
      }
    } else {
      iput += nz;
    }
    irow = mwork[irow].suc;
  }

  return (iput);
} /* c_ekkrwcs */
void c_ekkrwct(const EKKfactinfo *fact, double *dluval, int *hcoli, int *mrstrt,
  const int *hinrow, const EKKHlink *mwork,
  const EKKHlink *rlink,
  const short *msort, double *dsort,
  int nlast, int xnewro)
{
#if 0
  int *hcoli	= fact->xecadr;
  double *dluval	= fact->xeeadr;
  double *dvalpv = fact->kw3adr;
  int *mrstrt	= fact->xrsadr;
  int *hrowi	= fact->xeradr;
  int *mcstrt	= fact->xcsadr;
  int *hinrow	= fact->xrnadr;
  int *hincol	= fact->xcnadr;
  int *hpivro	= fact->krpadr;
  int *hpivco	= fact->kcpadr;
#endif
  int i, k, k1, nz, icol;
  int kmax;
  int irow, iput;
  int ilook;
  const int nrow = fact->nrow;

  iput = xnewro;
  irow = nlast;
  kmax = nrow - fact->npivots;
  for (i = 1; i <= nrow; ++i) {
    nz = hinrow[irow];
    k1 = mrstrt[irow] - 1;
    if (rlink[irow].pre < 0) {
      /* pivoted on already */
      iput -= nz;
      if (k1 != iput) {
        mrstrt[irow] = iput + 1;
        for (k = nz; k >= 1; --k) {
          dluval[iput + k] = dluval[k1 + k];
          hcoli[iput + k] = hcoli[k1 + k];
        }
      }
    } else {
      /* not pivoted - going dense */
      iput -= kmax;
      mrstrt[irow] = iput + 1;
      c_ekkdzero(kmax, &dsort[1]);
      for (k = 1; k <= nz; ++k) {
        icol = hcoli[k1 + k];
        ilook = msort[icol];
        dsort[ilook] = dluval[k1 + k];
      }
      c_ekkdcpy(kmax,
        (dsort + 1), (dluval + iput + 1));
    }
    irow = mwork[irow].pre;
  }
} /* c_ekkrwct */
/*     takes Uwe's modern structures and puts them back 20 years */
int c_ekkshff(EKKfactinfo *fact,
  EKKHlink *clink, EKKHlink *rlink,
  int xnewro)
{
  int *hpivro = fact->krpadr;

  int i, j;
  int nbas, icol;
  int ipiv;
  const int nrow = fact->nrow;
  int nsing;

  for (i = 1; i <= nrow; ++i) {
    j = -rlink[i].pre;
    rlink[i].pre = j;
    if (j > 0 && j <= nrow) {
      hpivro[j] = i;
    }
    j = -clink[i].pre;
    clink[i].pre = j;
  }
  /* hpivro[j] is now (hopefully) the row that was pivoted on step j */
  /* rlink[i].pre is the step in which row i was pivoted */

  nbas = 0;
  nsing = 0;
  /* Decide if permutation wanted */
  fact->first_dense = nrow - fact->ndenuc + 1 + 1;
  fact->last_dense = nrow;

  /* rlink[].suc is dead at this point */

  /*
   * replace the the basis index
   * with the pivot (or permuted) index generated by factorization.
   * This eventually goes into mpermu.
   */
  for (icol = 1; icol <= nrow; ++icol) {
    int ibasis = icol;
    ipiv = clink[ibasis].pre;

    if (0 < ipiv && ipiv <= nrow) {
      rlink[ibasis].suc = ipiv;
      ++nbas;
    }
  }

  nsing = nrow - nbas;
  if (nsing > 0) {
    abort();
  }

  /* if we reach here, then rlink[1..nrow].suc == clink[1..nrow].pre */

  /* switch off sparse update if any dense section */
  {
    const int notMuchRoom = (fact->nnentu + xnewro + 10 > fact->nnetas - fact->nnentl);

    /* must be same as in c_ekkshfv */
    if (fact->ndenuc || notMuchRoom || nrow < C_EKK_GO_SPARSE) {
#if PRINT_DEBUG
      if (fact->if_sparse_update) {
        printf("**** Switching off sparse update - dense - c_ekkshff\n");
      }
#endif
      fact->if_sparse_update = 0;
    }
  }

  /* hpivro[1..nrow] is not read by c_ekkshfv */
  c_ekkshfv(fact,
    rlink, clink,
    xnewro);

  return (0);
} /* c_ekkshff */
/* sorts on indices dragging elements with */
static void c_ekk_sort2(int *key, double *array2, int number)
{
  int minsize = 10;
  int n = number;
  int sp;
  int *v = key;
  int *m, t;
  int *ls[32], *rs[32];
  int *l, *r, c;
  double it;
  int j;
  /*check already sorted  */
#ifndef LONG_MAX
#define LONG_MAX 0x7fffffff;
#endif
  int last = -LONG_MAX;
  for (j = 0; j < number; j++) {
    if (key[j] >= last) {
      last = key[j];
    } else {
      break;
    } /* endif */
  } /* endfor */
  if (j == number) {
    return;
  } /* endif */
  sp = 0;
  ls[sp] = v;
  rs[sp] = v + (n - 1);
  while (sp >= 0) {
    if (rs[sp] - ls[sp] > minsize) {
      l = ls[sp];
      r = rs[sp];
      m = l + (r - l) / 2;
      if (*l > *m) {
        t = *l;
        *l = *m;
        *m = t;
        it = array2[l - v];
        array2[l - v] = array2[m - v];
        array2[m - v] = it;
      }
      if (*m > *r) {
        t = *m;
        *m = *r;
        *r = t;
        it = array2[m - v];
        array2[m - v] = array2[r - v];
        array2[r - v] = it;
        if (*l > *m) {
          t = *l;
          *l = *m;
          *m = t;
          it = array2[l - v];
          array2[l - v] = array2[m - v];
          array2[m - v] = it;
        }
      }
      c = *m;
      while (r - l > 1) {
        while (*(++l) < c)
          ;
        while (*(--r) > c)
          ;
        t = *l;
        *l = *r;
        *r = t;
        it = array2[l - v];
        array2[l - v] = array2[r - v];
        array2[r - v] = it;
      }
      l = r - 1;
      if (l < m) {
        ls[sp + 1] = ls[sp];
        rs[sp + 1] = l;
        ls[sp] = r;
      } else {
        ls[sp + 1] = r;
        rs[sp + 1] = rs[sp];
        rs[sp] = l;
      }
      sp++;
    } else
      sp--;
  }
  for (l = v, m = v + (n - 1); l < m; l++) {
    if (*l > *(l + 1)) {
      c = *(l + 1);
      it = array2[(l - v) + 1];
      for (r = l; r >= v && *r > c; r--) {
        *(r + 1) = *r;
        array2[(r - v) + 1] = array2[(r - v)];
      }
      *(r + 1) = c;
      array2[(r - v) + 1] = it;
    }
  }
}
/*     For each row compute reciprocal of pivot element and  take out of */
/*     Also use HLINK(1 to permute column numbers */
/*     and HPIVRO to permute row numbers */
/*     Sort into column order as was stored by row */
/*     If Assembler then shift row numbers in L by 3 */
/*     Put column numbers in U for L-U update */
/*     and multiply U elements by - reciprocal of pivot element */
/*     and set up backward pointers for pivot rows */
void c_ekkshfv(EKKfactinfo *fact,
  EKKHlink *rlink, EKKHlink *clink,
  int xnewro)
{
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  double *dvalpv = fact->kw3adr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *hpivro = fact->krpadr;
  int *hpivco = fact->kcpadr;
  double *dpermu = fact->kadrpm;
  double *de2val = fact->xe2adr ? fact->xe2adr - 1 : 0;
  int nnentu = fact->nnentu;
  int xnetal = fact->xnetal;

  int numberSlacks; /* numberSlacks not read */

  int i, j, k, kk, nel;
  int nroom;
  bool need_more_space;
  int ndenuc = fact->ndenuc;
  int if_sparse_update = fact->if_sparse_update;
  int nnentl = fact->nnentl;
  int nnetas = fact->nnetas;

  int *ihlink = (reinterpret_cast< int * >(clink)) + 1; /* can't use rlink for simple loop below */

  const int nrow = fact->nrow;
  const int maxinv = fact->maxinv;

  /* this is not just a temporary - c_ekkbtrn etc use this */
  int *mpermu = (reinterpret_cast< int * >(dpermu + nrow)) + 1;

  int *temp = ihlink + nrow;
  int *temp2 = temp + nrow;
  const int notMuchRoom = (nnentu + xnewro + 10 > nnetas - nnentl);

  /* compress hlink and make simpler */
  for (i = 1; i <= nrow; ++i) {
    mpermu[i] = rlink[i].pre;
    ihlink[i] = rlink[i].suc;
  }
  /* mpermu[i] == the step in which row i was pivoted */
  /* ihlink[i] == the step in which col i was pivoted */

  /* must be same as in c_ekkshff */
  if (fact->ndenuc || notMuchRoom || nrow < C_EKK_GO_SPARSE) {
    int ninbas;

    /* CHANGE COLUMN NUMBERS AND FILL IN RECIPROCALS */
    /* ALSO RECOMPUTE NUMBER IN COLUMN */
    /* initialize with a fake pivot in each column */
    c_ekkscpy_0_1(nrow, 1, &hincol[1]);

    if (notMuchRoom) {
      fact->eta_size = static_cast< int >(1.05 * fact->eta_size);

      /* eta_size can be no larger than maxNNetas */
      if (fact->maxNNetas > 0 && fact->eta_size > fact->maxNNetas) {
        fact->eta_size = fact->maxNNetas;
      }
    } /* endif */

    /* For each row compute reciprocal of pivot element and take out of U */
    /* Also use ihlink to permute column numbers */
    /* the rows are not stored compactly or in order,
     * so we have to find out where the last one is stored */
    ninbas = 0;
    for (i = 1; i <= nrow; ++i) {
      int jpiv = mpermu[i];
      int nin = hinrow[i];
      int krs = mrstrt[i];
      int kre = krs + nin;

      temp[jpiv] = krs;
      temp2[jpiv] = nin;

      ninbas = CoinMax(kre, ninbas);

      /* c_ekktria etc ensure that the first row entry is the pivot */
      dvalpv[jpiv] = 1. / dluval[krs];
      hcoli[krs] = 0; /* probably needed for c_ekkrowq */
      /* room for the pivot has already been allocated, so hincol ok */

      for (kk = krs + 1; kk < kre; ++kk) {
        int j = ihlink[hcoli[kk]];
        hcoli[kk] = j; /* permute the col index */
        hrowi[kk] = jpiv; /* permute the row index */
        ++hincol[j];
      }
    }
    /* temp [mpermu[i]] == mrstrt[i] */
    /* temp2[mpermu[i]] == hinrow[i] */

    ninbas--; /* ???? */
    c_ekkscpy(nrow, &temp[1], &mrstrt[1]);
    c_ekkscpy(nrow, &temp2[1], &hinrow[1]);

    /* now mrstrt, hinrow, hcoli and hrowi have been permuted */

    /* Sort into column order as was stored by row */
    /* There will be an empty entry in front of each each column,
     * because we initialized hincol to 1s, and c_ekkrowq fills in
     * entries from the back */
    c_ekkrowq(hcoli, hrowi, dluval, mcstrt, hincol, nrow, ninbas);

    /* The shuffle zeroed out column pointers */
    /* Put them back for L-U update */
    /* Also multiply U elements by - reciprocal of pivot element */
    /* Also decrement mcstrt/hincol to give "real" sizes */
    for (i = 1; i <= nrow; ++i) {
      int kx = --mcstrt[i];
      nel = --hincol[i];
      hrowi[kx] = nel;
      dluval[kx] = dvalpv[i];
#ifndef NO_SHIFT
      for (int j = kx + 1; j <= kx + nel; j++)
        hrowi[j] = SHIFT_INDEX(hrowi[j]);
#endif
    }

    /* sort dense part */
    for (i = nrow - ndenuc + 1; i <= nrow; i++) {
      int kx = mcstrt[i] + 1; /* "real" entries start after pivot */
      int nel = hincol[i];
      c_ekk_sort2(&hrowi[kx], &dluval[kx], nel);
    }

    /* Recompute number in U */
    nnentu = mcstrt[nrow] + hincol[nrow];
    mcstrt[nrow + 4] = nnentu + 1; /* magic - AND DEAD */

    /* as not much room switch off fast etas */
    mrstrt[1] = 0; /* magic */
    fact->rows_ok = false;
    i = nrow + maxinv + 5; /* DEAD */
  } else {
    /* *************************************** */
    /*       enough memory to do a bit faster */
    /*       For each row compute reciprocal of pivot element and */
    /*       take out of U */
    /*       Also use HLINK(1 to permute column numbers */
    int ninbas = 0;
    int ilast; /* last available entry */
    int spareSpace;
    double *dluval2;
    /*int * hlink2 = ihlink+nrow;
      int * mrstrt2 = hlink2+nrow;*/
    /* mwork has order of row copy */
    EKKHlink *mwork = (reinterpret_cast< EKKHlink * >(fact->kw1adr)) - 1;
    fact->rows_ok = true;

    if (if_sparse_update) {
      ilast = nnetas - nnentl;
    } else {
      /* missing out nnentl stuff */
      ilast = nnetas;
    }
    spareSpace = ilast - nnentu;
    need_more_space = false;
    /*     save clean row copy if enough room */
    nroom = (spareSpace) / nrow;
    if (nrow < 10000) {
      if (nroom < 10) {
        need_more_space = true;
      }
    } else {
      if (nroom < 5 && !if_sparse_update) {
        need_more_space = true;
      }
    }
    if (nroom > CoinMin(50, maxinv)) {
      need_more_space = false;
    }
    if (need_more_space) {
      if (if_sparse_update) {
        int i1 = fact->eta_size + 10 * nrow;
        fact->eta_size = static_cast< int >(1.2 * fact->eta_size);
        if (i1 > fact->eta_size) {
          fact->eta_size = i1;
        }
      } else {
        fact->eta_size = static_cast< int >(1.05 * fact->eta_size);
      }
    } else {
      if (nroom < 11) {
        if (if_sparse_update) {
          int i1 = fact->eta_size + (11 - nroom) * nrow;
          fact->eta_size = static_cast< int >(1.2 * fact->eta_size);
          if (i1 > fact->eta_size) {
            fact->eta_size = i1;
          }
        }
      }
    }
    if (fact->maxNNetas > 0 && fact->eta_size > fact->maxNNetas) {
      fact->eta_size = fact->maxNNetas;
    }
    {
      /* we can swap de2val and dluval to save copying */
      int *eta_last = mpermu + nrow * 2 + 3;
      int *eta_next = eta_last + nrow + 2;
      int last = 0;
      eta_last[0] = -1;
      if (nnentl) {
        /* went into c_ekkcmfc - if not then in order */
        int next;
        /*next=mwork[((nrow+1)<<1)+1];*/
        next = mwork[nrow + 1].pre;
#ifdef DEBUG
        j = mrstrt[next];
#endif
        for (i = 1; i <= nrow; ++i) {
          int iperm = mpermu[next];
          eta_next[last] = iperm;
          eta_last[iperm] = last;
          temp[iperm] = mrstrt[next];
          temp2[iperm] = hinrow[next];
#ifdef DEBUG
          if (mrstrt[next] != j)
            abort();
          j = mrstrt[next] + hinrow[next];
#endif
          /*next= mwork[(next<<1)+2];*/
          next = mwork[next].suc;
          last = iperm;
        }
      } else {
#ifdef DEBUG
        j = 0;
#endif
        for (i = 1; i <= nrow; ++i) {
          int iperm = mpermu[i];
          eta_next[last] = iperm;
          eta_last[iperm] = last;
          temp[iperm] = mrstrt[i];
          temp2[iperm] = hinrow[i];
          last = iperm;
#ifdef DEBUG
          if (mrstrt[i] <= j)
            abort();
          if (i > 1 && mrstrt[i] != j + hinrow[i - 1])
            abort();
          j = mrstrt[i];
#endif
        }
      }
      eta_next[last] = nrow + 1;
      eta_last[nrow + 1] = last;
      eta_next[nrow + 1] = nrow + 2;
      c_ekkscpy(nrow, &temp[1], &mrstrt[1]);
      c_ekkscpy(nrow, &temp2[1], &hinrow[1]);
      i = eta_last[nrow + 1];
      ninbas = mrstrt[i] + hinrow[i] - 1;
#ifdef DEBUG
      if (spareSpace < ninbas) {
        abort();
      }
#endif
      c_ekkizero(nrow, &hincol[1]);
#ifdef DEBUG
      for (i = nrow; i > 0; i--) {
        int krs = mrstrt[i];
        int jpiv = hcoli[krs];
        if (ihlink[jpiv] != i)
          abort();
      }
#endif
      for (i = 1; i <= ninbas; ++i) {
        k = hcoli[i];
        k = ihlink[k];
#ifdef DEBUG
        if (k <= 0 || k > nrow)
          abort();
#endif
        hcoli[i] = k;
        hincol[k]++;
      }
#ifdef DEBUG
      for (i = nrow; i > 0; i--) {
        int krs = mrstrt[i];
        int jpiv = hcoli[krs];
        if (jpiv != i)
          abort();
        if (krs > ninbas)
          abort();
      }
#endif
      /*       Sort into column order as was stored by row */
      k = 1;
      /*        Position */
      for (kk = 1; kk <= nrow; ++kk) {
        nel = hincol[kk];
        mcstrt[kk] = k;
        hrowi[k] = nel - 1;
        k += hincol[kk];
        hincol[kk] = 0;
      }
      if (de2val) {
        dluval2 = de2val;
      } else {
        dluval2 = dluval + ninbas;
      }
      nnentu = k - 1;
      mcstrt[nrow + 4] = nnentu + 1;
      /* create column copy */
      for (i = nrow; i > 0; i--) {
        int krs = mrstrt[i];
        int kre = krs + hinrow[i];
        hinrow[i]--;
        mrstrt[i]++;
        {
          int kx = mcstrt[i];
          /*nel = hincol[i];
	    if (hrowi[kx]!=nel) abort();
	    hrowi[kx] = nel-1;*/
          dluval2[kx] = 1.0 / dluval[krs];
          /*hincol[i]=0;*/
          for (kk = krs + 1; kk < kre; ++kk) {
            int j = hcoli[kk];
            int iput = hincol[j] + 1;
            hincol[j] = iput;
            iput += mcstrt[j];
            hrowi[iput] = SHIFT_INDEX(i);
            dluval2[iput] = dluval[kk];
          }
        }
      }
      if (de2val) {
        double *a = dluval;
        double *address;
        /* move first down */
        i = eta_next[0];
        {
          int krs = mrstrt[i];
          nel = hinrow[i];
          for (j = 1; j <= nel; j++) {
            hcoli[j] = hcoli[j + krs - 1];
            dluval[j] = dluval[j + krs - 1];
          }
        }
        mrstrt[i] = 1;
        /****** swap dluval and de2val !!!! ******/
        /* should work even for dspace */
        /* move L part across */
        address = fact->xeeadr + 1;
        fact->xeeadr = fact->xe2adr - 1;
        fact->xe2adr = address;
        if (nnentl) {
          int n = xnetal - nrow - maxinv - 5;
          int j1, j2;
          int *mcstrt2 = mcstrt + nrow + maxinv + 4;
          j2 = mcstrt2[1];
          j1 = mcstrt2[n + 1] + 1;
#if 0
	  memcpy(de2val+j1,dluval+j1,(j2-j1+1)*sizeof(double));
#else
          c_ekkdcpy(j2 - j1 + 1,
            (dluval + j1), (de2val + j1));
#endif
        }
        dluval = de2val;
        de2val = a;
      } else {
        /* copy down dluval */
#if 0
	memcpy(&dluval[1],&dluval2[1],ninbas*sizeof(double));
#else
        c_ekkdcpy(ninbas,
          (dluval2 + 1), (dluval + 1));
#endif
      }
      /* sort dense part */
      for (i = nrow - ndenuc + 1; i <= nrow; i++) {
        int kx = mcstrt[i] + 1;
        int nel = hincol[i];
        c_ekk_sort2(&hrowi[kx], &dluval[kx], nel);
      }
    }
    mrstrt[nrow + 1] = ilast + 1;
  }
  /* Find first non slack */
  for (i = 1; i <= nrow; ++i) {
    int kcs = mcstrt[i];
    if (hincol[i] != 0 || dluval[kcs] != SLACK_VALUE) {
      break;
    }
  }
  numberSlacks = i - 1;
  {
    /* set slacks to 1 */
    int *array = fact->krpadr + (fact->nrowmx + 2);
    int nSet = (numberSlacks) >> 5;
    int n2 = (fact->nrowmx + 32) >> 5;
    int i;
    memset(array, 0xff, nSet * sizeof(int));
    memset(array + nSet, 0, (n2 - nSet) * sizeof(int));
    for (i = nSet << 5; i <= numberSlacks; i++)
      c_ekk_Set(array, i);
    c_ekk_Unset(array, fact->nrow + 1); /* make sure off end not slack */
#ifndef NDEBUG
    for (i = 1; i <= numberSlacks; i++)
      assert(c_ekk_IsSet(array, i));
    for (; i <= fact->nrow; i++)
      assert(!c_ekk_IsSet(array, i));
#endif
  }

  /* and set up backward pointers */
  /* clean up HPIVCO for fancy assembler stuff */
  /* xnetal was initialized to nrow + maxinv + 4 in c_ekktria, and grows */
  c_ekkscpy_0_1(maxinv + 1, 1, &hpivco[nrow + 4]); /* magic */

  hpivco[xnetal] = 1;
  /* shuffle down for gaps so can get rid of hpivco for L */
  {
    const int lstart = nrow + maxinv + 5;
    int n = xnetal - lstart; /* number of L entries */
    int add, iel;
    int *hpivco_L = &hpivco[lstart];
    int *mcstrt_L = &mcstrt[lstart];
    if (nnentl) {
      /* elements of L were stored in descending order in dluval/hcoli */
      int kle = mcstrt_L[0];
      int kls = mcstrt_L[n] + 1;

      if (if_sparse_update) {
        int i2, iel;
        int *mrstrt2 = &mrstrt[nrow];

        /* need row copy of L */
        /* hpivro is spare for counts; just used as a temp buffer */
        c_ekkizero(nrow, &hpivro[1]);

        /* permute L indices; count L row lengths */
        for (iel = kls; iel <= kle; ++iel) {
          int jrow = mpermu[UNSHIFT_INDEX(hrowi[iel])];
          hpivro[jrow]++;
          hrowi[iel] = SHIFT_INDEX(jrow);
        }
        {
          int ibase = nnetas - nnentl + 1;
          int firstDoRow = 0;
          for (i = 1; i <= nrow; i++) {
            mrstrt2[i] = ibase;
            if (hpivro[i] && !firstDoRow) {
              firstDoRow = i;
            }
            ibase += hpivro[i];
            hpivro[i] = mrstrt2[i];
          }
          if (!firstDoRow) {
            firstDoRow = nrow + 1;
          }
          mrstrt2[i] = ibase;
          fact->firstDoRow = firstDoRow;
        }
        i2 = mcstrt_L[n];
        for (i = n - 1; i >= 0; --i) {
          int i1 = mcstrt_L[i];
          int ipiv = hpivco_L[i];
          ipiv = mpermu[ipiv];
          hpivco_L[i] = ipiv;
          for (iel = i2; iel < i1; iel++) {
            int irow = UNSHIFT_INDEX(hrowi[iel + 1]);
            int iput = hpivro[irow];
            hpivro[irow] = iput + 1;
            hcoli[iput] = ipiv;
            de2val[iput] = dluval[iel + 1];
          }
          i2 = i1;
        }
      } else {
        /* just permute row numbers */

        for (j = 0; j < n; ++j) {
          hpivco_L[j] = mpermu[hpivco_L[j]];
        }
        for (iel = kls; iel <= kle; ++iel) {
          int jrow = mpermu[UNSHIFT_INDEX(hrowi[iel])];
          hrowi[iel] = SHIFT_INDEX(jrow);
        }
      }

      add = hpivco_L[n - 1] - hpivco_L[0] - n + 1;
      if (add) {
        int i;
        int last = hpivco_L[n - 1];
        int laststart = mcstrt_L[n];
        int base = hpivco_L[0] - 1;
        /* adjust so numbers match */
        mcstrt_L -= base;
        hpivco_L -= base;
        mcstrt_L[last] = laststart;
        for (i = n - 1; i >= 0; i--) {
          int ipiv = hpivco_L[i + base];
          while (ipiv < last) {
            mcstrt_L[last - 1] = laststart;
            hpivco_L[last - 1] = last;
            last--;
          }
          laststart = mcstrt_L[i + base];
          mcstrt_L[last - 1] = laststart;
          hpivco_L[last - 1] = last;
          last--;
        }
        xnetal += add;
      }
    }
    //int lstart=fact->lstart;
    //const int * COIN_RESTRICT hpivco	= fact->kcpadr;
    fact->firstLRow = hpivco[lstart];
  }
  fact->nnentu = nnentu;
  fact->xnetal = xnetal;
  /* now we have xnetal * we can set up pointers */
  clp_setup_pointers(fact);

  /* this is the array used in c_ekkbtrn; it is passed to c_ekkbtju as hpivco.
   * this gets modified by F-T as we pivot columns in and out.
   */
  {
    /* do new hpivco */
    int *hpivco_new = fact->kcpadr + 1;
    int *back = &fact->kcpadr[2 * nrow + maxinv + 4];
    /* set zeroth to stop illegal read */
    back[0] = 1;

    hpivco_new[nrow + 1] = nrow + 1; /* deliberate loop for dense tests */
    hpivco_new[0] = 1;

    for (i = 1; i <= nrow; i++) {
      hpivco_new[i] = i + 1;
      back[i + 1] = i;
    }
    back[1] = 0;

    fact->first_dense = CoinMax(fact->first_dense, 4);
    fact->numberSlacks = numberSlacks;
    fact->lastSlack = numberSlacks;
    fact->firstNonSlack = hpivco_new[numberSlacks];
  }

  /* also zero out permute region and nonzero */
  c_ekkdzero(nrow, (dpermu + 1));

  if (if_sparse_update) {
    char *nonzero = reinterpret_cast< char * >(&mpermu[nrow + 1]); /* used in c_ekkbtrn */
    /*c_ekkizero(nrow,(int *)nonzero);*/
    c_ekkczero(nrow, nonzero);
    /*memset(nonzero,0,nrow*sizeof(int));*/ /* for faster method */
  }
  for (i = 1; i <= nrow; ++i) {
    hpivro[mpermu[i]] = i;
  }

} /* c_ekkshfv */

static void c_ekkclcp1(const int *hcol, const int *mrstrt,
  int *hrow, int *mcstrt,
  int *hincol, int nnrow, int nncol,
  int ninbas)
{
  int i, j, kc, kr, kre, krs, icol;
  int iput;

  /* Create columnwise storage of row indices */

  kc = 1;
  for (j = 1; j <= nncol; ++j) {
    mcstrt[j] = kc;
    kc += hincol[j];
    hincol[j] = 0;
  }
  mcstrt[nncol + 1] = ninbas + 1;

  for (i = 1; i <= nnrow; ++i) {
    krs = mrstrt[i];
    kre = mrstrt[i + 1] - 1;
    for (kr = krs; kr <= kre; ++kr) {
      icol = hcol[kr];
      iput = hincol[icol];
      hincol[icol] = iput + 1;
      iput += mcstrt[icol];
      hrow[iput] = i;
    }
  }
} /* c_ekkclcp */
inline void c_ekkclcp2(const int *hcol, const double *dels, const int *mrstrt,
  int *hrow, double *dels2, int *mcstrt,
  int *hincol, int nnrow, int nncol,
  int ninbas)
{
  int i, j, kc, kr, kre, krs, icol;
  int iput;

  /* Create columnwise storage of row indices */

  kc = 1;
  for (j = 1; j <= nncol; ++j) {
    mcstrt[j] = kc;
    kc += hincol[j];
    hincol[j] = 0;
  }
  mcstrt[nncol + 1] = ninbas + 1;

  for (i = 1; i <= nnrow; ++i) {
    krs = mrstrt[i];
    kre = mrstrt[i + 1] - 1;
    for (kr = krs; kr <= kre; ++kr) {
      icol = hcol[kr];
      iput = hincol[icol];
      hincol[icol] = iput + 1;
      iput += mcstrt[icol];
      hrow[iput] = i;
      dels2[iput] = dels[kr];
    }
  }
} /* c_ekkclcp */
int c_ekkslcf(register const EKKfactinfo *fact)
{
  int *hrow = fact->xeradr;
  int *hcol = fact->xecadr;
  double *dels = fact->xeeadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *mrstrt = fact->xrsadr;
  int *mcstrt = fact->xcsadr;
  const int nrow = fact->nrow;
  int ninbas;
  /* space for etas */
  const int nnetas = fact->nnetas;
  ninbas = mcstrt[nrow + 1] - 1;

  /* Now sort */
  if (ninbas << 1 > nnetas) {
    /* Put it in row order */
    int i, k;
    c_ekkrowq(hrow, hcol, dels, mrstrt, hinrow, nrow, ninbas);
    k = 1;
    for (i = 1; i <= nrow; ++i) {
      mrstrt[i] = k;
      k += hinrow[i];
    }
    mrstrt[nrow + 1] = k;

    /* make a column copy without the extra values */
    c_ekkclcp1(hcol, mrstrt, hrow, mcstrt, hincol, nrow, nrow, ninbas);
  } else {
    /* Move elements up memory */
    c_ekkdcpy(ninbas,
      (dels + 1), (dels + ninbas + 1));

    /* make a row copy with the extra values */
    c_ekkclcp2(hrow, &dels[ninbas], mcstrt, hcol, dels, mrstrt, hinrow, nrow, nrow, ninbas);
  }
  return (ninbas);
} /* c_ekkslcf */
/*     Uwe H. Suhl, September 1986 */
/*     Removes lower and upper triangular factors from the matrix. */
/*     Code for routine: 102 */
/*     Return codes: */
/*	0: ok */
/*      -5: not enough space in row file */
/*      7: pivot too small - col sing */
/*
 * This selects singleton columns and rows for the LU factorization.
 * Singleton columns require no
 *
 * (1) Note that columns are processed using a queue, not a stack;
 * this produces better pivots.
 *
 * (2) At most nrows elements are ever entered into the queue.
 *
 * (3) When pivoting singleton columns, every column that is part of
 * the pivot row is shortened by one, including the singleton column
 * itself; the hincol entries are updated appropriately.
 * Thus, pivoting on a singleton column may create other singleton columns
 * (but not singleton rows).
 * The dual property is true for rows.
 *
 * (4) Row entries (hrowi) are not changed when pivoting singleton columns.
 * Singleton columns that are created as a result of pivoting the
 * rows of other singleton columns will therefore have row entries
 * corresponding to those pivoted rows.  Since we need to find the
 * row entry for the row being pivoted, we have to
 * search its row entries for the one whose hlink entry indicates
 * that it has not yet been pivoted.
 *
 * (9) As a result of pivoting columns, sections in hrowi corresponding to
 * pivoted columns are no longer needed, and entries in sections
 * for non-pivoted columns may have entries corresponding to pivoted rows.
 * This is why hrowi needs to be compacted.
 *
 * (5) When the row_pre and col_pre fields of the hlink struct contain
 * negative values, they indicate that the row has been pivoted, and
 * the negative of that value is the pivot order.
 * That is the only use for these fields in this routine.
 *
 * (6) This routine assumes that hlink is initialized to zeroes.
 * Under this assumption, the following is an invariant in this routine:
 *
 *	(clink[i].pre < 0) ==> (hincol[i]==0)
 *
 * The converse is not true; see (15).
 *
 * The dual is also true, but only while pivoting singletong rows,
 * since we don't update hinrow while pivoting columns;
 * THESE VALUES ARE USED LATER, BUT I DON'T UNDERSTAND HOW YET.
 *
 * (7) hpivco is used for two purposes.  The low end is used to implement the
 * queue when pivoting columns; the high end is used to hold eta-matrix
 * entries.
 *
 * (8) As a result of pivoting columns, for all i:1<=i<=nrow, either
 *	hinrow[i] has not changed
 * or
 *	hinrow[i] = 0
 * This is another way of saying that pivoting singleton columns cannot
 * create singleton rows.
 * The dual holds for hincol after pivoting rows.
 *
 * (10) In constrast to (4), while pivoting rows we
 * do not let the hcoli get out-of-date.  That is because as part of
 * the process of numerical pivoting we have to find the row entries
 * for all the rows in the pivot column, so we may as well keep the
 * entries up to date.  This is done by moving the last column entry
 * for each row into the entry that was used for the pivot column.
 *
 * (11) When pivoting a column, we must find the pivot row entry in
 * its row table.  Sometimes we search for other things at the same time.
 * The same is true for pivoting columns.  This search should never
 * fail.
 *
 * (12) Information concerning the eta matrices is stored in the high
 * ends of arrays that are also used to store information concerning
 * the basis; these arrays are: hpivco, mcstrt, dluval and hcoli.
 * Information is only stored in these arrays as a part of pivoting
 * singleton rows, since the only thing that needs to be saved as
 * a part of pivoting singleton columns is which rows and columns were chosen,
 * and this is stored in hlink.
 * Since they have to share the same array, the eta information grows
 * downward instead of upward. Eventually, eta information may grow
 * down to the top of the basis information.  As pivoting proceeds,
 * more and more of this information is no longer needed, so when this
 * happens we can try compacting the arrays to see if we can recover
 * enough space.  lstart points at the bottom entry in the arrays,
 * xnewro/xnewco at the top of the basis information, and each time we
 * pivot a singleton row we know that we will need exactly as many new
 * entries as there are rows in the pivot column, so we can easily
 * determine if we need more room.  The variable maxinv may be used
 * to reserve extra room when inversion starts.
 *
 * (13) Eta information is stored in a fashion that is similar to how
 * matrices are stored.  There is one entry in hpivco and mcstrt for
 * each eta (other than the initial ones for singleton columns and
 * for singleton rows that turn out to be singleton columns),
 * in the order they were chosen.  hpivco records the pivot row,
 * and mcstrt points at the first entry in the other two arrays
 * for this row.  dluval contains the actual eta values for the column,
 * and hcoli the rows these values were in.
 * These entries in mcstrt and hpivco grow upward; they start above
 * the entries used to store basis information.
 * (Actually, I don't see why they need to start maxinv+4 entries past the top).
 *
 * (14) c_ekkrwco assumes that invalidated hrowi/hcoli entries contain 0.
 *
 * (15) When pivoting singleton columns, it may possibly happen
 * that a row with all singleton column entries is created.
 * In this case, all of the columns will be enqueued, and pivoting
 * on any of them eliminates the rest, without their being chosen
 * as pivots.  The dual holds for singleton rows.
 * DOES THIS INDICATE A SINGULARITY?
 *
 * (15) There are some aspects of the implementation that I find odd.
 * hrowi is not set to 0 for pivot rows while pivoting singleton columns,
 * which would make sense to me.  Things don't work if this isn't done,
 * so the information is used somehow later on.  Also, the information
 * for the pivot column is shifted to the front of the pivot row
 * when pivoting singleton columns; this is also necessary for reasons
 * I don't understand.
 */
int c_ekktria(EKKfactinfo *fact,
  EKKHlink *rlink,
  EKKHlink *clink,
  int *nsingp,
  int *xnewcop, int *xnewrop,
  int *ncompactionsp,
  const int ninbas)
{
  const int nrow = fact->nrow;
  const int maxinv = fact->maxinv;
  int *hcoli = fact->xecadr;
  double *dluval = fact->xeeadr;
  int *mrstrt = fact->xrsadr;
  int *hrowi = fact->xeradr;
  int *mcstrt = fact->xcsadr;
  int *hinrow = fact->xrnadr;
  int *hincol = fact->xcnadr;
  int *stack = fact->krpadr; /* normally hpivro */
  int *hpivco = fact->kcpadr;
  const double drtpiv = fact->drtpiv;
  CoinZeroN(reinterpret_cast< int * >(rlink + 1), static_cast< int >(nrow * (sizeof(EKKHlink) / sizeof(int))));
  CoinZeroN(reinterpret_cast< int * >(clink + 1), static_cast< int >(nrow * (sizeof(EKKHlink) / sizeof(int))));

  fact->npivots = 0;
  /*      Use NUSPIK to keep sum of deactivated row counts */
  fact->nuspike = 0;
  int xnetal = nrow + maxinv + 4;
  int xnewro = mrstrt[nrow] + hinrow[nrow] - 1;
  int xnewco = xnewro;
  int kmxeta = ninbas;
  int ncompactions = 0;

  int i, j, k, kc, kce, kcs, npr;
  double pivot;
  int kipis, kipie, kjpis, kjpie, knprs, knpre;
  int ipivot, jpivot, stackc, stackr;
#ifndef NDEBUG
  int kpivot = -1;
#else
  int kpivot = -1;
#endif
  int epivco, kstart, maxstk;
  int irtcod = 0;
  int lastSlack = 0;

  int lstart = fact->nnetas + 1;
  /*int nnentu	= ninbas; */
  int lstart_minus_nnentu = lstart - ninbas;
  /* do initial column singletons - as can do faster */
  for (jpivot = 1; jpivot <= nrow; ++jpivot) {
    if (hincol[jpivot] == 1) {
      ipivot = hrowi[mcstrt[jpivot]];
      if (ipivot > lastSlack) {
        lastSlack = ipivot;
      } else {
        /* so we can't put a structural over a slack */
        break;
      }
      kipis = mrstrt[ipivot];
#if 1
      assert(hcoli[kipis] == jpivot);
#else
      if (hcoli[kipis] != jpivot) {
        kpivot = kipis + 1;
        while (hcoli[kpivot] != jpivot)
          kpivot++;
#ifdef DEBUG
        kipie = kipis + hinrow[ipivot];
        if (kpivot >= kipie) {
          abort();
        }
#endif
        pivot = dluval[kpivot];
        dluval[kpivot] = dluval[kipis];
        dluval[kipis] = pivot;
        hcoli[kpivot] = hcoli[kipis];
        hcoli[kipis] = jpivot;
      }
#endif
      if (dluval[kipis] == SLACK_VALUE) {
        /* record the new pivot row and column */
        ++fact->npivots;
        rlink[ipivot].pre = -fact->npivots;
        clink[jpivot].pre = -fact->npivots;
        hincol[jpivot] = 0;
        fact->nuspike += hinrow[ipivot];
      } else {
        break;
      }
    } else {
      break;
    }
  }
  /* Fill queue with other column singletons and clean up */
  maxstk = 0;
  for (j = 1; j <= nrow; ++j) {
    if (hincol[j]) {
      int n = 0;
      kcs = mcstrt[j];
      kce = mcstrt[j + 1];
      for (k = kcs; k < kce; ++k) {
        if (!(rlink[hrowi[k]].pre < 0)) {
          n++;
        }
      }
      hincol[j] = n;
      if (n == 1) {
        /* we just created a new singleton column - enqueue it */
        ++maxstk;
        stack[maxstk] = j;
      }
    }
  }
  stackc = 0; /* (1) */

  while (!(stackc >= maxstk)) { /* (1) */
    /* dequeue the next entry */
    ++stackc;
    jpivot = stack[stackc];

    /* (15) */
    if (hincol[jpivot] != 0) {

      for (k = mcstrt[jpivot]; rlink[hrowi[k]].pre < 0; k++) {
        /* (4) */
      }
      ipivot = hrowi[k];

      /* All the columns in this row are being shortened. */
      kipis = mrstrt[ipivot];
      kipie = kipis + hinrow[ipivot];
      for (k = kipis; k < kipie; ++k) {
        j = hcoli[k];
        --hincol[j]; /* (3) (6) */

        if (j == jpivot) {
          kpivot = k; /* (11) */
        } else if (hincol[j] == 1) {
          /* we just created a new singleton column - enqueue it */
          ++maxstk;
          stack[maxstk] = j;
        }
      }

      /* record the new pivot row and column */
      ++fact->npivots;
      rlink[ipivot].pre = -fact->npivots;
      clink[jpivot].pre = -fact->npivots;

      fact->nuspike += hinrow[ipivot];

      /* check the pivot */
      assert(kpivot > 0);
      pivot = dluval[kpivot];
      if (fabs(pivot) < drtpiv) {
        irtcod = 7;
        ++(*nsingp);
        rlink[ipivot].pre = -nrow - 1;
        clink[jpivot].pre = -nrow - 1;
      }

      /* swap the pivot column entry with the first one. */
      /* I don't know why. */
      dluval[kpivot] = dluval[kipis];
      dluval[kipis] = pivot;
      hcoli[kpivot] = hcoli[kipis];
      hcoli[kipis] = jpivot;
    }
  }
  /* (8) */

  /* The entire basis may already be triangular */
  if (fact->npivots < nrow) {

    /* (9) */
    kstart = 0;
    for (j = 1; j <= nrow; ++j) {
      if (!(clink[j].pre < 0)) {
        kcs = mcstrt[j];
        kce = mcstrt[j + 1];

        mcstrt[j] = kstart + 1;

        for (k = kcs; k < kce; ++k) {
          if (!(rlink[hrowi[k]].pre < 0)) {
            ++kstart;
            hrowi[kstart] = hrowi[k];
          }
        }
        hincol[j] = kstart - mcstrt[j] + 1;
      }
    }
    xnewco = kstart;

    /* Fill stack with initial row singletons that haven't been pivoted away */
    stackr = 0;
    for (i = 1; i <= nrow; ++i) {
      if (!(rlink[i].pre < 0) && (hinrow[i] == 1)) {
        ++stackr;
        stack[stackr] = i;
      }
    }

    while (!(stackr <= 0)) {
      ipivot = stack[stackr];
      assert(ipivot);
      --stackr;

#if 1
      assert(rlink[ipivot].pre >= 0);
#else
      /* This test is probably unnecessary:  rlink[i].pre < 0 ==> hinrow[i]==0 */
      if (rlink[ipivot].pre < 0) {
        continue;
      }
#endif

      /* (15) */
      if (hinrow[ipivot] != 0) {

        /* This is a singleton row, which means it has exactly one column */
        jpivot = hcoli[mrstrt[ipivot]];

        kjpis = mcstrt[jpivot];
        epivco = hincol[jpivot] - 1;
        hincol[jpivot] = 0; /* this column is being pivoted away */

        /* (11) */
        kjpie = kjpis + epivco;
        for (k = kjpis; k <= kjpie; ++k) {
          if (ipivot == hrowi[k])
            break;
        }
        /* ASSERT (k <= kjpie) */

        /* move the last row entry for the pivot column into the pivot row's entry */
        /* I don't know why */
        hrowi[k] = hrowi[kjpie];

        /* invalidate the (old) last row entry of the pivot column */
        /* I don't know why */
        hrowi[kjpie] = 0;

        /* (12) */
        if (!(xnewro + epivco < lstart)) {
          int kstart;

          if (!(epivco < lstart_minus_nnentu)) {
            irtcod = -5;
            break;
          }
          kstart = c_ekkrwco(fact, dluval, hcoli, mrstrt, hinrow, xnewro);
          ++ncompactions;
          kmxeta += (xnewro - kstart) << 1;
          xnewro = kstart;
        }
        if (!(xnewco + epivco < lstart)) {
          if (!(epivco < lstart_minus_nnentu)) {
            irtcod = -5;
            break;
          }
          xnewco = c_ekkclco(fact, hrowi, mcstrt, hincol, xnewco);
          ++ncompactions;

          /*     HINCOL MAY HAVE CHANGED ??? (JJHF) */
          epivco = hincol[jpivot];
        }

        /* record the new pivot row and column */
        ++fact->npivots;
        rlink[ipivot].pre = -fact->npivots;
        clink[jpivot].pre = -fact->npivots;

        /* no update for nuspik */

        /* check the pivot */
        pivot = dluval[mrstrt[ipivot]];
        if (fabs(pivot) < drtpiv) {
          /* If the pivot is too small, reject it, but keep going */
          irtcod = 7;
          rlink[ipivot].pre = -nrow - 1;
          clink[jpivot].pre = -nrow - 1;
        }

        /* Perform numerical part of elimination. */
        if (!(epivco <= 0)) {
          ++xnetal;
          mcstrt[xnetal] = lstart - 1;
          hpivco[xnetal] = ipivot;
          pivot = -1.f / pivot;

          kcs = mcstrt[jpivot];
          kce = kcs + epivco - 1;
          hincol[jpivot] = 0;

          for (kc = kcs; kc <= kce; ++kc) {
            npr = hrowi[kc];

            /* why bother? */
            hrowi[kc] = 0;

            --hinrow[npr]; /* (3) */
            if (hinrow[npr] == 1) {
              /* this may create new singleton rows */
              ++stackr;
              stack[stackr] = npr;
            }

            /* (11) */
            knprs = mrstrt[npr];
            knpre = knprs + hinrow[npr];
            for (k = knprs; k <= knpre; ++k) {
              if (jpivot == hcoli[k]) {
                kpivot = k;
                break;
              }
            }
            /* ASSERT (kpivot <= knpre) */

            {
              /* (10) */
              double elemnt = dluval[kpivot];
              dluval[kpivot] = dluval[knpre];
              hcoli[kpivot] = hcoli[knpre];

              hcoli[knpre] = 0; /* (14) */

              /* store elementary row transformation */
              --lstart;
              dluval[lstart] = elemnt * pivot;
              hcoli[lstart] = npr;
            }
          }
        }
      }
    }
  }
  /* (8) */

  *xnewcop = xnewco;
  *xnewrop = xnewro;
  fact->xnetal = xnetal;
  fact->nnentu = lstart - lstart_minus_nnentu;
  fact->kmxeta = kmxeta;
  *ncompactionsp = ncompactions;

  return (irtcod);
} /* c_ekktria */
#endif

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