77 lines
2.4 KiB
C++
77 lines
2.4 KiB
C++
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
#include "lmp_f2c.h"
|
|
static integer c__1 = 1;
|
|
static doublereal c_b8 = -1.;
|
|
int dgetf2_(integer *m, integer *n, doublereal *a, integer *lda, integer *ipiv, integer *info)
|
|
{
|
|
integer a_dim1, a_offset, i__1, i__2, i__3;
|
|
doublereal d__1;
|
|
integer i__, j, jp;
|
|
extern int dger_(integer *, integer *, doublereal *, doublereal *, integer *, doublereal *,
|
|
integer *, doublereal *, integer *),
|
|
dscal_(integer *, doublereal *, doublereal *, integer *);
|
|
doublereal sfmin;
|
|
extern int dswap_(integer *, doublereal *, integer *, doublereal *, integer *);
|
|
extern doublereal dlamch_(char *, ftnlen);
|
|
extern integer idamax_(integer *, doublereal *, integer *);
|
|
extern int xerbla_(char *, integer *, ftnlen);
|
|
a_dim1 = *lda;
|
|
a_offset = 1 + a_dim1;
|
|
a -= a_offset;
|
|
--ipiv;
|
|
*info = 0;
|
|
if (*m < 0) {
|
|
*info = -1;
|
|
} else if (*n < 0) {
|
|
*info = -2;
|
|
} else if (*lda < max(1, *m)) {
|
|
*info = -4;
|
|
}
|
|
if (*info != 0) {
|
|
i__1 = -(*info);
|
|
xerbla_((char *)"DGETF2", &i__1, (ftnlen)6);
|
|
return 0;
|
|
}
|
|
if (*m == 0 || *n == 0) {
|
|
return 0;
|
|
}
|
|
sfmin = dlamch_((char *)"S", (ftnlen)1);
|
|
i__1 = min(*m, *n);
|
|
for (j = 1; j <= i__1; ++j) {
|
|
i__2 = *m - j + 1;
|
|
jp = j - 1 + idamax_(&i__2, &a[j + j * a_dim1], &c__1);
|
|
ipiv[j] = jp;
|
|
if (a[jp + j * a_dim1] != 0.) {
|
|
if (jp != j) {
|
|
dswap_(n, &a[j + a_dim1], lda, &a[jp + a_dim1], lda);
|
|
}
|
|
if (j < *m) {
|
|
if ((d__1 = a[j + j * a_dim1], abs(d__1)) >= sfmin) {
|
|
i__2 = *m - j;
|
|
d__1 = 1. / a[j + j * a_dim1];
|
|
dscal_(&i__2, &d__1, &a[j + 1 + j * a_dim1], &c__1);
|
|
} else {
|
|
i__2 = *m - j;
|
|
for (i__ = 1; i__ <= i__2; ++i__) {
|
|
a[j + i__ + j * a_dim1] /= a[j + j * a_dim1];
|
|
}
|
|
}
|
|
}
|
|
} else if (*info == 0) {
|
|
*info = j;
|
|
}
|
|
if (j < min(*m, *n)) {
|
|
i__2 = *m - j;
|
|
i__3 = *n - j;
|
|
dger_(&i__2, &i__3, &c_b8, &a[j + 1 + j * a_dim1], &c__1, &a[j + (j + 1) * a_dim1], lda,
|
|
&a[j + 1 + (j + 1) * a_dim1], lda);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|