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lammps/lib/linalg/dlauu2.cpp

78 lines
2.6 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
static doublereal c_b7 = 1.;
static integer c__1 = 1;
int dlauu2_(char *uplo, integer *n, doublereal *a, integer *lda, integer *info, ftnlen uplo_len)
{
integer a_dim1, a_offset, i__1, i__2, i__3;
integer i__;
doublereal aii;
extern doublereal ddot_(integer *, doublereal *, integer *, doublereal *, integer *);
extern int dscal_(integer *, doublereal *, doublereal *, integer *);
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern int dgemv_(char *, integer *, integer *, doublereal *, doublereal *, integer *,
doublereal *, integer *, doublereal *, doublereal *, integer *, ftnlen);
logical upper;
extern int xerbla_(char *, integer *, ftnlen);
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
*info = 0;
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;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_((char *)"DLAUU2", &i__1, (ftnlen)6);
return 0;
}
if (*n == 0) {
return 0;
}
if (upper) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
aii = a[i__ + i__ * a_dim1];
if (i__ < *n) {
i__2 = *n - i__ + 1;
a[i__ + i__ * a_dim1] =
ddot_(&i__2, &a[i__ + i__ * a_dim1], lda, &a[i__ + i__ * a_dim1], lda);
i__2 = i__ - 1;
i__3 = *n - i__;
dgemv_((char *)"N", &i__2, &i__3, &c_b7, &a[(i__ + 1) * a_dim1 + 1], lda,
&a[i__ + (i__ + 1) * a_dim1], lda, &aii, &a[i__ * a_dim1 + 1], &c__1,
(ftnlen)1);
} else {
dscal_(&i__, &aii, &a[i__ * a_dim1 + 1], &c__1);
}
}
} else {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
aii = a[i__ + i__ * a_dim1];
if (i__ < *n) {
i__2 = *n - i__ + 1;
a[i__ + i__ * a_dim1] =
ddot_(&i__2, &a[i__ + i__ * a_dim1], &c__1, &a[i__ + i__ * a_dim1], &c__1);
i__2 = *n - i__;
i__3 = i__ - 1;
dgemv_((char *)"T", &i__2, &i__3, &c_b7, &a[i__ + 1 + a_dim1], lda,
&a[i__ + 1 + i__ * a_dim1], &c__1, &aii, &a[i__ + a_dim1], lda, (ftnlen)1);
} else {
dscal_(&i__, &aii, &a[i__ + a_dim1], lda);
}
}
}
return 0;
}
#ifdef __cplusplus
}
#endif