src/gromacs/linearalgebra/gmx_lapack/strti2.c

   1 #include "../gmx_blas.h"
   2 #include "../gmx_lapack.h"
   3 #include "lapack_limits.h"
   4
   5 void
   6 F77_FUNC(strti2,STRTI2)(const char *uplo,
   7         const char *diag,
   8         int *n,
   9         float *a,
  10         int *lda,
  11         int *info)
  12 {
  13     int a_dim1, a_offset, i__1, i__2;
  14
  15     int j;
  16     float ajj;
  17     int upper, nounit;
  18     int c__1 = 1;
  19
  20
  21     a_dim1 = *lda;
  22     a_offset = 1 + a_dim1;
  23     a -= a_offset;
  24
  25     *info = 0;
  26     upper = (*uplo=='U' || *uplo=='u');
  27     nounit = (*diag=='N' || *diag=='n');
  28
  29     if (*info != 0) {
  30         i__1 = -(*info);
  31         return;
  32     }
  33
  34     if (upper) {
  35
  36         i__1 = *n;
  37         for (j = 1; j <= i__1; ++j) {
  38             if (nounit) {
  39                 a[j + j * a_dim1] = 1. / a[j + j * a_dim1];
  40                 ajj = -a[j + j * a_dim1];
  41             } else {
  42                 ajj = -1.;
  43             }
  44
  45             i__2 = j - 1;
  46             F77_FUNC(strmv,STRMV)("Upper", "No transpose", diag, &i__2, &a[a_offset], lda, &
  47                     a[j * a_dim1 + 1], &c__1);
  48             i__2 = j - 1;
  49             F77_FUNC(sscal,SSCAL)(&i__2, &ajj, &a[j * a_dim1 + 1], &c__1);
  50         }
  51     } else {
  52
  53         for (j = *n; j >= 1; --j) {
  54             if (nounit) {
  55                 a[j + j * a_dim1] = 1. / a[j + j * a_dim1];
  56                 ajj = -a[j + j * a_dim1];
  57             } else {
  58                 ajj = -1.;
  59             }
  60             if (j < *n) {
  61
  62                 i__1 = *n - j;
  63                 F77_FUNC(strmv,STRMV)("Lower", "No transpose", diag, &i__1, &a[j + 1 + (j +
  64                         1) * a_dim1], lda, &a[j + 1 + j * a_dim1], &c__1);
  65                 i__1 = *n - j;
  66                 F77_FUNC(sscal,SSCAL)(&i__1, &ajj, &a[j + 1 + j * a_dim1], &c__1);
  67             }
  68         }
  69     }
  70     return;
  71 }