Files
lammps/lib/linalg/dsyr2.cpp

121 lines
3.7 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
int dsyr2_(char *uplo, integer *n, doublereal *alpha, doublereal *x, integer *incx, doublereal *y,
integer *incy, doublereal *a, integer *lda, ftnlen uplo_len)
{
integer a_dim1, a_offset, i__1, i__2;
integer i__, j, ix, iy, jx, jy, kx, ky, info;
doublereal temp1, temp2;
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern int xerbla_(char *, integer *, ftnlen);
--x;
--y;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
info = 0;
if (!lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1) && !lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
info = 1;
} else if (*n < 0) {
info = 2;
} else if (*incx == 0) {
info = 5;
} else if (*incy == 0) {
info = 7;
} else if (*lda < max(1, *n)) {
info = 9;
}
if (info != 0) {
xerbla_((char *)"DSYR2 ", &info, (ftnlen)6);
return 0;
}
if (*n == 0 || *alpha == 0.) {
return 0;
}
if (*incx != 1 || *incy != 1) {
if (*incx > 0) {
kx = 1;
} else {
kx = 1 - (*n - 1) * *incx;
}
if (*incy > 0) {
ky = 1;
} else {
ky = 1 - (*n - 1) * *incy;
}
jx = kx;
jy = ky;
}
if (lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1)) {
if (*incx == 1 && *incy == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[j] != 0. || y[j] != 0.) {
temp1 = *alpha * y[j];
temp2 = *alpha * x[j];
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] = a[i__ + j * a_dim1] + x[i__] * temp1 + y[i__] * temp2;
}
}
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[jx] != 0. || y[jy] != 0.) {
temp1 = *alpha * y[jy];
temp2 = *alpha * x[jx];
ix = kx;
iy = ky;
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] = a[i__ + j * a_dim1] + x[ix] * temp1 + y[iy] * temp2;
ix += *incx;
iy += *incy;
}
}
jx += *incx;
jy += *incy;
}
}
} else {
if (*incx == 1 && *incy == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[j] != 0. || y[j] != 0.) {
temp1 = *alpha * y[j];
temp2 = *alpha * x[j];
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] = a[i__ + j * a_dim1] + x[i__] * temp1 + y[i__] * temp2;
}
}
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[jx] != 0. || y[jy] != 0.) {
temp1 = *alpha * y[jy];
temp2 = *alpha * x[jx];
ix = jx;
iy = jy;
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] = a[i__ + j * a_dim1] + x[ix] * temp1 + y[iy] * temp2;
ix += *incx;
iy += *incy;
}
}
jx += *incx;
jy += *incy;
}
}
}
return 0;
}
#ifdef __cplusplus
}
#endif