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lammps/lib/linalg/zungqr.cpp

131 lines
4.6 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
static integer c__1 = 1;
static integer c_n1 = -1;
static integer c__3 = 3;
static integer c__2 = 2;
int zungqr_(integer *m, integer *n, integer *k, doublecomplex *a, integer *lda, doublecomplex *tau,
doublecomplex *work, integer *lwork, integer *info)
{
integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
integer i__, j, l, ib, nb, ki, kk, nx, iws, nbmin, iinfo;
extern int zung2r_(integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *,
doublecomplex *, integer *),
xerbla_(char *, integer *, ftnlen);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *,
ftnlen, ftnlen);
extern int zlarfb_(char *, char *, char *, char *, integer *, integer *, integer *,
doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *,
integer *, doublecomplex *, integer *, ftnlen, ftnlen, ftnlen, ftnlen);
integer ldwork;
extern int zlarft_(char *, char *, integer *, integer *, doublecomplex *, integer *,
doublecomplex *, doublecomplex *, integer *, ftnlen, ftnlen);
integer lwkopt;
logical lquery;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--tau;
--work;
*info = 0;
nb = ilaenv_(&c__1, (char *)"ZUNGQR", (char *)" ", m, n, k, &c_n1, (ftnlen)6, (ftnlen)1);
lwkopt = max(1, *n) * nb;
work[1].r = (doublereal)lwkopt, work[1].i = 0.;
lquery = *lwork == -1;
if (*m < 0) {
*info = -1;
} else if (*n < 0 || *n > *m) {
*info = -2;
} else if (*k < 0 || *k > *n) {
*info = -3;
} else if (*lda < max(1, *m)) {
*info = -5;
} else if (*lwork < max(1, *n) && !lquery) {
*info = -8;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_((char *)"ZUNGQR", &i__1, (ftnlen)6);
return 0;
} else if (lquery) {
return 0;
}
if (*n <= 0) {
work[1].r = 1., work[1].i = 0.;
return 0;
}
nbmin = 2;
nx = 0;
iws = *n;
if (nb > 1 && nb < *k) {
i__1 = 0, i__2 = ilaenv_(&c__3, (char *)"ZUNGQR", (char *)" ", m, n, k, &c_n1, (ftnlen)6, (ftnlen)1);
nx = max(i__1, i__2);
if (nx < *k) {
ldwork = *n;
iws = ldwork * nb;
if (*lwork < iws) {
nb = *lwork / ldwork;
i__1 = 2,
i__2 = ilaenv_(&c__2, (char *)"ZUNGQR", (char *)" ", m, n, k, &c_n1, (ftnlen)6, (ftnlen)1);
nbmin = max(i__1, i__2);
}
}
}
if (nb >= nbmin && nb < *k && nx < *k) {
ki = (*k - nx - 1) / nb * nb;
i__1 = *k, i__2 = ki + nb;
kk = min(i__1, i__2);
i__1 = *n;
for (j = kk + 1; j <= i__1; ++j) {
i__2 = kk;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
a[i__3].r = 0., a[i__3].i = 0.;
}
}
} else {
kk = 0;
}
if (kk < *n) {
i__1 = *m - kk;
i__2 = *n - kk;
i__3 = *k - kk;
zung2r_(&i__1, &i__2, &i__3, &a[kk + 1 + (kk + 1) * a_dim1], lda, &tau[kk + 1], &work[1],
&iinfo);
}
if (kk > 0) {
i__1 = -nb;
for (i__ = ki + 1; i__1 < 0 ? i__ >= 1 : i__ <= 1; i__ += i__1) {
i__2 = nb, i__3 = *k - i__ + 1;
ib = min(i__2, i__3);
if (i__ + ib <= *n) {
i__2 = *m - i__ + 1;
zlarft_((char *)"F", (char *)"C", &i__2, &ib, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[1],
&ldwork, (ftnlen)1, (ftnlen)1);
i__2 = *m - i__ + 1;
i__3 = *n - i__ - ib + 1;
zlarfb_((char *)"L", (char *)"N", (char *)"F", (char *)"C", &i__2, &i__3, &ib, &a[i__ + i__ * a_dim1], lda,
&work[1], &ldwork, &a[i__ + (i__ + ib) * a_dim1], lda, &work[ib + 1],
&ldwork, (ftnlen)1, (ftnlen)1, (ftnlen)1, (ftnlen)1);
}
i__2 = *m - i__ + 1;
zung2r_(&i__2, &ib, &ib, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[1], &iinfo);
i__2 = i__ + ib - 1;
for (j = i__; j <= i__2; ++j) {
i__3 = i__ - 1;
for (l = 1; l <= i__3; ++l) {
i__4 = l + j * a_dim1;
a[i__4].r = 0., a[i__4].i = 0.;
}
}
}
}
work[1].r = (doublereal)iws, work[1].i = 0.;
return 0;
}
#ifdef __cplusplus
}
#endif