156 lines
4.5 KiB
C++
156 lines
4.5 KiB
C++
#ifdef __cplusplus
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extern "C" {
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#endif
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#include "lmp_f2c.h"
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int dsymv_(char *uplo, integer *n, doublereal *alpha, doublereal *a, integer *lda, doublereal *x,
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integer *incx, doublereal *beta, doublereal *y, integer *incy, ftnlen uplo_len)
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{
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integer a_dim1, a_offset, i__1, i__2;
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integer i__, j, ix, iy, jx, jy, kx, ky, info;
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doublereal temp1, temp2;
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extern logical lsame_(char *, char *, ftnlen, ftnlen);
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extern int xerbla_(char *, integer *, ftnlen);
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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--x;
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--y;
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info = 0;
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if (!lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1) && !lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
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info = 1;
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} else if (*n < 0) {
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info = 2;
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} else if (*lda < max(1, *n)) {
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info = 5;
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} else if (*incx == 0) {
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info = 7;
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} else if (*incy == 0) {
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info = 10;
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}
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if (info != 0) {
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xerbla_((char *)"DSYMV ", &info, (ftnlen)6);
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return 0;
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}
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if (*n == 0 || *alpha == 0. && *beta == 1.) {
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return 0;
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}
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if (*incx > 0) {
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kx = 1;
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} else {
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kx = 1 - (*n - 1) * *incx;
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}
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if (*incy > 0) {
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ky = 1;
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} else {
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ky = 1 - (*n - 1) * *incy;
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}
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if (*beta != 1.) {
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if (*incy == 1) {
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if (*beta == 0.) {
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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y[i__] = 0.;
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}
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} else {
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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y[i__] = *beta * y[i__];
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}
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}
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} else {
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iy = ky;
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if (*beta == 0.) {
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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y[iy] = 0.;
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iy += *incy;
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}
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} else {
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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y[iy] = *beta * y[iy];
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iy += *incy;
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}
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}
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}
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}
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if (*alpha == 0.) {
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return 0;
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}
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if (lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1)) {
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if (*incx == 1 && *incy == 1) {
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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temp1 = *alpha * x[j];
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temp2 = 0.;
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i__2 = j - 1;
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for (i__ = 1; i__ <= i__2; ++i__) {
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y[i__] += temp1 * a[i__ + j * a_dim1];
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temp2 += a[i__ + j * a_dim1] * x[i__];
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}
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y[j] = y[j] + temp1 * a[j + j * a_dim1] + *alpha * temp2;
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}
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} else {
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jx = kx;
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jy = ky;
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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temp1 = *alpha * x[jx];
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temp2 = 0.;
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ix = kx;
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iy = ky;
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i__2 = j - 1;
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for (i__ = 1; i__ <= i__2; ++i__) {
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y[iy] += temp1 * a[i__ + j * a_dim1];
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temp2 += a[i__ + j * a_dim1] * x[ix];
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ix += *incx;
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iy += *incy;
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}
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y[jy] = y[jy] + temp1 * a[j + j * a_dim1] + *alpha * temp2;
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jx += *incx;
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jy += *incy;
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}
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}
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} else {
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if (*incx == 1 && *incy == 1) {
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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temp1 = *alpha * x[j];
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temp2 = 0.;
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y[j] += temp1 * a[j + j * a_dim1];
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i__2 = *n;
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for (i__ = j + 1; i__ <= i__2; ++i__) {
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y[i__] += temp1 * a[i__ + j * a_dim1];
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temp2 += a[i__ + j * a_dim1] * x[i__];
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}
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y[j] += *alpha * temp2;
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}
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} else {
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jx = kx;
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jy = ky;
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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temp1 = *alpha * x[jx];
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temp2 = 0.;
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y[jy] += temp1 * a[j + j * a_dim1];
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ix = jx;
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iy = jy;
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i__2 = *n;
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for (i__ = j + 1; i__ <= i__2; ++i__) {
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ix += *incx;
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iy += *incy;
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y[iy] += temp1 * a[i__ + j * a_dim1];
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temp2 += a[i__ + j * a_dim1] * x[ix];
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}
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y[jy] += *alpha * temp2;
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jx += *incx;
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jy += *incy;
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}
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}
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}
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return 0;
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}
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#ifdef __cplusplus
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}
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#endif
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