1 /**********************************************************************
2 lapack_dstegr1.c:
3
4 lapack_dstegr1.c is a subroutine to find eigenvalues and eigenvectors
5 of tridiagonlized real matrix using lapack's routines dstegr.
6
7 Log of lapack_dstegr1.c:
8
9 Dec/24/2004 Released by T.Ozaki
10
11 ***********************************************************************/
12
13 #include <stdio.h>
14 #include <math.h>
15 #include <stdlib.h>
16 #include "openmx_common.h"
17 #include "lapack_prototypes.h"
18 #include "mpi.h"
19
20
lapack_dstegr1(INTEGER N,INTEGER EVmax,double * D,double * E,double * W,double ** ev)21 void lapack_dstegr1(INTEGER N, INTEGER EVmax, double *D, double *E, double *W, double **ev)
22 {
23 int i,j;
24
25 char *JOBZ="V";
26 char *RANGE="A";
27
28 double VL,VU; /* dummy */
29 INTEGER IL,IU;
30 double ABSTOL_GR=LAPACK_ABSTOL;
31 INTEGER M;
32 double *Z;
33 INTEGER LDZ;
34 INTEGER *ISUPPZ;
35 INTEGER LWORK;
36 double *WORK;
37 INTEGER *IWORK;
38 INTEGER LIWORK;
39 INTEGER INFO;
40
41 IL = 1;
42 IU = N;
43
44 M = IU - IL + 1;
45 LDZ = N;
46
47 Z = (double*)malloc(sizeof(double)*LDZ*N);
48 ISUPPZ = (INTEGER*)malloc(sizeof(INTEGER)*2*M);
49
50 LWORK = 18*N;
51 LIWORK = 10*N;
52 WORK = (double*)malloc(sizeof(double)*LWORK);
53 IWORK = (INTEGER*)malloc(sizeof(INTEGER)*LIWORK);
54
55 F77_NAME(dstegr,DSTEGR)( JOBZ, RANGE, &N, D, E, &VL, &VU, &IL, &IU, &ABSTOL_GR,
56 &M, W, Z, &LDZ, ISUPPZ, WORK, &LWORK, IWORK, &LIWORK, &INFO );
57
58 /* store eigenvectors */
59
60 for (i=0; i<N; i++) {
61 for (j=0; j<N; j++) {
62 ev[i+1][j+1]= Z[i*N+j];
63 }
64 }
65
66 /* shift ko by 1 */
67 for (i=N; i>=1; i--){
68 W[i]= W[i-1];
69 }
70
71 if (INFO>0) {
72 /* printf("\n error in dstegr_, info=%d\n\n",INFO); */
73 }
74 if (INFO<0) {
75 printf("info=%d in dstegr_\n",INFO);
76 MPI_Finalize();
77 exit(0);
78 }
79
80 free(Z);
81 free(ISUPPZ);
82 free(WORK);
83 free(IWORK);
84 }
85