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lammps/lib/linalg/dorgtr.cpp

116 lines
3.5 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
static integer c__1 = 1;
static integer c_n1 = -1;
int dorgtr_(char *uplo, integer *n, doublereal *a, integer *lda, doublereal *tau, doublereal *work,
integer *lwork, integer *info, ftnlen uplo_len)
{
integer a_dim1, a_offset, i__1, i__2, i__3;
integer i__, j, nb;
extern logical lsame_(char *, char *, ftnlen, ftnlen);
integer iinfo;
logical upper;
extern int xerbla_(char *, integer *, ftnlen);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *,
ftnlen, ftnlen);
extern int dorgql_(integer *, integer *, integer *, doublereal *, integer *, doublereal *,
doublereal *, integer *, integer *),
dorgqr_(integer *, integer *, integer *, doublereal *, integer *, doublereal *,
doublereal *, integer *, integer *);
integer lwkopt;
logical lquery;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--tau;
--work;
*info = 0;
lquery = *lwork == -1;
upper = lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1);
if (!upper && !lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
*info = -1;
} else if (*n < 0) {
*info = -2;
} else if (*lda < max(1, *n)) {
*info = -4;
} else {
i__1 = 1, i__2 = *n - 1;
if (*lwork < max(i__1, i__2) && !lquery) {
*info = -7;
}
}
if (*info == 0) {
if (upper) {
i__1 = *n - 1;
i__2 = *n - 1;
i__3 = *n - 1;
nb = ilaenv_(&c__1, (char *)"DORGQL", (char *)" ", &i__1, &i__2, &i__3, &c_n1, (ftnlen)6, (ftnlen)1);
} else {
i__1 = *n - 1;
i__2 = *n - 1;
i__3 = *n - 1;
nb = ilaenv_(&c__1, (char *)"DORGQR", (char *)" ", &i__1, &i__2, &i__3, &c_n1, (ftnlen)6, (ftnlen)1);
}
i__1 = 1, i__2 = *n - 1;
lwkopt = max(i__1, i__2) * nb;
work[1] = (doublereal)lwkopt;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_((char *)"DORGTR", &i__1, (ftnlen)6);
return 0;
} else if (lquery) {
return 0;
}
if (*n == 0) {
work[1] = 1.;
return 0;
}
if (upper) {
i__1 = *n - 1;
for (j = 1; j <= i__1; ++j) {
i__2 = j - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] = a[i__ + (j + 1) * a_dim1];
}
a[*n + j * a_dim1] = 0.;
}
i__1 = *n - 1;
for (i__ = 1; i__ <= i__1; ++i__) {
a[i__ + *n * a_dim1] = 0.;
}
a[*n + *n * a_dim1] = 1.;
i__1 = *n - 1;
i__2 = *n - 1;
i__3 = *n - 1;
dorgql_(&i__1, &i__2, &i__3, &a[a_offset], lda, &tau[1], &work[1], lwork, &iinfo);
} else {
for (j = *n; j >= 2; --j) {
a[j * a_dim1 + 1] = 0.;
i__1 = *n;
for (i__ = j + 1; i__ <= i__1; ++i__) {
a[i__ + j * a_dim1] = a[i__ + (j - 1) * a_dim1];
}
}
a[a_dim1 + 1] = 1.;
i__1 = *n;
for (i__ = 2; i__ <= i__1; ++i__) {
a[i__ + a_dim1] = 0.;
}
if (*n > 1) {
i__1 = *n - 1;
i__2 = *n - 1;
i__3 = *n - 1;
dorgqr_(&i__1, &i__2, &i__3, &a[(a_dim1 << 1) + 2], lda, &tau[1], &work[1], lwork,
&iinfo);
}
}
work[1] = (doublereal)lwkopt;
return 0;
}
#ifdef __cplusplus
}
#endif