1 /* stpmv.f -- translated by f2c (version 20061008).
2 You must link the resulting object file with libf2c:
3 on Microsoft Windows system, link with libf2c.lib;
4 on Linux or Unix systems, link with .../path/to/libf2c.a -lm
5 or, if you install libf2c.a in a standard place, with -lf2c -lm
6 -- in that order, at the end of the command line, as in
7 cc *.o -lf2c -lm
8 Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
9
10 http://www.netlib.org/f2c/libf2c.zip
11 */
12
13 #include "f2c.h"
14 #include "blaswrap.h"
15
stpmv_(char * uplo,char * trans,char * diag,integer * n,real * ap,real * x,integer * incx)16 /* Subroutine */ int stpmv_(char *uplo, char *trans, char *diag, integer *n,
17 real *ap, real *x, integer *incx)
18 {
19 /* System generated locals */
20 integer i__1, i__2;
21
22 /* Local variables */
23 integer i__, j, k, kk, ix, jx, kx, info;
24 real temp;
25 extern logical lsame_(char *, char *);
26 extern /* Subroutine */ int xerbla_(char *, integer *);
27 logical nounit;
28
29 /* .. Scalar Arguments .. */
30 /* .. */
31 /* .. Array Arguments .. */
32 /* .. */
33
34 /* Purpose */
35 /* ======= */
36
37 /* STPMV performs one of the matrix-vector operations */
38
39 /* x := A*x, or x := A'*x, */
40
41 /* where x is an n element vector and A is an n by n unit, or non-unit, */
42 /* upper or lower triangular matrix, supplied in packed form. */
43
44 /* Arguments */
45 /* ========== */
46
47 /* UPLO - CHARACTER*1. */
48 /* On entry, UPLO specifies whether the matrix is an upper or */
49 /* lower triangular matrix as follows: */
50
51 /* UPLO = 'U' or 'u' A is an upper triangular matrix. */
52
53 /* UPLO = 'L' or 'l' A is a lower triangular matrix. */
54
55 /* Unchanged on exit. */
56
57 /* TRANS - CHARACTER*1. */
58 /* On entry, TRANS specifies the operation to be performed as */
59 /* follows: */
60
61 /* TRANS = 'N' or 'n' x := A*x. */
62
63 /* TRANS = 'T' or 't' x := A'*x. */
64
65 /* TRANS = 'C' or 'c' x := A'*x. */
66
67 /* Unchanged on exit. */
68
69 /* DIAG - CHARACTER*1. */
70 /* On entry, DIAG specifies whether or not A is unit */
71 /* triangular as follows: */
72
73 /* DIAG = 'U' or 'u' A is assumed to be unit triangular. */
74
75 /* DIAG = 'N' or 'n' A is not assumed to be unit */
76 /* triangular. */
77
78 /* Unchanged on exit. */
79
80 /* N - INTEGER. */
81 /* On entry, N specifies the order of the matrix A. */
82 /* N must be at least zero. */
83 /* Unchanged on exit. */
84
85 /* AP - REAL array of DIMENSION at least */
86 /* ( ( n*( n + 1 ) )/2 ). */
87 /* Before entry with UPLO = 'U' or 'u', the array AP must */
88 /* contain the upper triangular matrix packed sequentially, */
89 /* column by column, so that AP( 1 ) contains a( 1, 1 ), */
90 /* AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) */
91 /* respectively, and so on. */
92 /* Before entry with UPLO = 'L' or 'l', the array AP must */
93 /* contain the lower triangular matrix packed sequentially, */
94 /* column by column, so that AP( 1 ) contains a( 1, 1 ), */
95 /* AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) */
96 /* respectively, and so on. */
97 /* Note that when DIAG = 'U' or 'u', the diagonal elements of */
98 /* A are not referenced, but are assumed to be unity. */
99 /* Unchanged on exit. */
100
101 /* X - REAL array of dimension at least */
102 /* ( 1 + ( n - 1 )*abs( INCX ) ). */
103 /* Before entry, the incremented array X must contain the n */
104 /* element vector x. On exit, X is overwritten with the */
105 /* tranformed vector x. */
106
107 /* INCX - INTEGER. */
108 /* On entry, INCX specifies the increment for the elements of */
109 /* X. INCX must not be zero. */
110 /* Unchanged on exit. */
111
112
113 /* Level 2 Blas routine. */
114
115 /* -- Written on 22-October-1986. */
116 /* Jack Dongarra, Argonne National Lab. */
117 /* Jeremy Du Croz, Nag Central Office. */
118 /* Sven Hammarling, Nag Central Office. */
119 /* Richard Hanson, Sandia National Labs. */
120
121
122 /* .. Parameters .. */
123 /* .. */
124 /* .. Local Scalars .. */
125 /* .. */
126 /* .. External Functions .. */
127 /* .. */
128 /* .. External Subroutines .. */
129 /* .. */
130
131 /* Test the input parameters. */
132
133 /* Parameter adjustments */
134 --x;
135 --ap;
136
137 /* Function Body */
138 info = 0;
139 if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
140 info = 1;
141 } else if (! lsame_(trans, "N") && ! lsame_(trans,
142 "T") && ! lsame_(trans, "C")) {
143 info = 2;
144 } else if (! lsame_(diag, "U") && ! lsame_(diag,
145 "N")) {
146 info = 3;
147 } else if (*n < 0) {
148 info = 4;
149 } else if (*incx == 0) {
150 info = 7;
151 }
152 if (info != 0) {
153 xerbla_("STPMV ", &info);
154 return 0;
155 }
156
157 /* Quick return if possible. */
158
159 if (*n == 0) {
160 return 0;
161 }
162
163 nounit = lsame_(diag, "N");
164
165 /* Set up the start point in X if the increment is not unity. This */
166 /* will be ( N - 1 )*INCX too small for descending loops. */
167
168 if (*incx <= 0) {
169 kx = 1 - (*n - 1) * *incx;
170 } else if (*incx != 1) {
171 kx = 1;
172 }
173
174 /* Start the operations. In this version the elements of AP are */
175 /* accessed sequentially with one pass through AP. */
176
177 if (lsame_(trans, "N")) {
178
179 /* Form x:= A*x. */
180
181 if (lsame_(uplo, "U")) {
182 kk = 1;
183 if (*incx == 1) {
184 i__1 = *n;
185 for (j = 1; j <= i__1; ++j) {
186 if (x[j] != 0.f) {
187 temp = x[j];
188 k = kk;
189 i__2 = j - 1;
190 for (i__ = 1; i__ <= i__2; ++i__) {
191 x[i__] += temp * ap[k];
192 ++k;
193 /* L10: */
194 }
195 if (nounit) {
196 x[j] *= ap[kk + j - 1];
197 }
198 }
199 kk += j;
200 /* L20: */
201 }
202 } else {
203 jx = kx;
204 i__1 = *n;
205 for (j = 1; j <= i__1; ++j) {
206 if (x[jx] != 0.f) {
207 temp = x[jx];
208 ix = kx;
209 i__2 = kk + j - 2;
210 for (k = kk; k <= i__2; ++k) {
211 x[ix] += temp * ap[k];
212 ix += *incx;
213 /* L30: */
214 }
215 if (nounit) {
216 x[jx] *= ap[kk + j - 1];
217 }
218 }
219 jx += *incx;
220 kk += j;
221 /* L40: */
222 }
223 }
224 } else {
225 kk = *n * (*n + 1) / 2;
226 if (*incx == 1) {
227 for (j = *n; j >= 1; --j) {
228 if (x[j] != 0.f) {
229 temp = x[j];
230 k = kk;
231 i__1 = j + 1;
232 for (i__ = *n; i__ >= i__1; --i__) {
233 x[i__] += temp * ap[k];
234 --k;
235 /* L50: */
236 }
237 if (nounit) {
238 x[j] *= ap[kk - *n + j];
239 }
240 }
241 kk -= *n - j + 1;
242 /* L60: */
243 }
244 } else {
245 kx += (*n - 1) * *incx;
246 jx = kx;
247 for (j = *n; j >= 1; --j) {
248 if (x[jx] != 0.f) {
249 temp = x[jx];
250 ix = kx;
251 i__1 = kk - (*n - (j + 1));
252 for (k = kk; k >= i__1; --k) {
253 x[ix] += temp * ap[k];
254 ix -= *incx;
255 /* L70: */
256 }
257 if (nounit) {
258 x[jx] *= ap[kk - *n + j];
259 }
260 }
261 jx -= *incx;
262 kk -= *n - j + 1;
263 /* L80: */
264 }
265 }
266 }
267 } else {
268
269 /* Form x := A'*x. */
270
271 if (lsame_(uplo, "U")) {
272 kk = *n * (*n + 1) / 2;
273 if (*incx == 1) {
274 for (j = *n; j >= 1; --j) {
275 temp = x[j];
276 if (nounit) {
277 temp *= ap[kk];
278 }
279 k = kk - 1;
280 for (i__ = j - 1; i__ >= 1; --i__) {
281 temp += ap[k] * x[i__];
282 --k;
283 /* L90: */
284 }
285 x[j] = temp;
286 kk -= j;
287 /* L100: */
288 }
289 } else {
290 jx = kx + (*n - 1) * *incx;
291 for (j = *n; j >= 1; --j) {
292 temp = x[jx];
293 ix = jx;
294 if (nounit) {
295 temp *= ap[kk];
296 }
297 i__1 = kk - j + 1;
298 for (k = kk - 1; k >= i__1; --k) {
299 ix -= *incx;
300 temp += ap[k] * x[ix];
301 /* L110: */
302 }
303 x[jx] = temp;
304 jx -= *incx;
305 kk -= j;
306 /* L120: */
307 }
308 }
309 } else {
310 kk = 1;
311 if (*incx == 1) {
312 i__1 = *n;
313 for (j = 1; j <= i__1; ++j) {
314 temp = x[j];
315 if (nounit) {
316 temp *= ap[kk];
317 }
318 k = kk + 1;
319 i__2 = *n;
320 for (i__ = j + 1; i__ <= i__2; ++i__) {
321 temp += ap[k] * x[i__];
322 ++k;
323 /* L130: */
324 }
325 x[j] = temp;
326 kk += *n - j + 1;
327 /* L140: */
328 }
329 } else {
330 jx = kx;
331 i__1 = *n;
332 for (j = 1; j <= i__1; ++j) {
333 temp = x[jx];
334 ix = jx;
335 if (nounit) {
336 temp *= ap[kk];
337 }
338 i__2 = kk + *n - j;
339 for (k = kk + 1; k <= i__2; ++k) {
340 ix += *incx;
341 temp += ap[k] * x[ix];
342 /* L150: */
343 }
344 x[jx] = temp;
345 jx += *incx;
346 kk += *n - j + 1;
347 /* L160: */
348 }
349 }
350 }
351 }
352
353 return 0;
354
355 /* End of STPMV . */
356
357 } /* stpmv_ */
358