--- /dev/null
+#include "clapack.h"
+
+/* Subroutine */ int dsymv_(char *uplo, integer *n, doublereal *alpha,
+ doublereal *a, integer *lda, doublereal *x, integer *incx, doublereal
+ *beta, doublereal *y, integer *incy)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, i__1, i__2;
+
+ /* Local variables */
+ integer i__, j, ix, iy, jx, jy, kx, ky, info;
+ doublereal temp1, temp2;
+ extern logical lsame_(char *, char *);
+ extern /* Subroutine */ int xerbla_(char *, integer *);
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DSYMV performs the matrix-vector operation */
+
+/* y := alpha*A*x + beta*y, */
+
+/* where alpha and beta are scalars, x and y are n element vectors and */
+/* A is an n by n symmetric matrix. */
+
+/* Arguments */
+/* ========== */
+
+/* UPLO - CHARACTER*1. */
+/* On entry, UPLO specifies whether the upper or lower */
+/* triangular part of the array A is to be referenced as */
+/* follows: */
+
+/* UPLO = 'U' or 'u' Only the upper triangular part of A */
+/* is to be referenced. */
+
+/* UPLO = 'L' or 'l' Only the lower triangular part of A */
+/* is to be referenced. */
+
+/* Unchanged on exit. */
+
+/* N - INTEGER. */
+/* On entry, N specifies the order of the matrix A. */
+/* N must be at least zero. */
+/* Unchanged on exit. */
+
+/* ALPHA - DOUBLE PRECISION. */
+/* On entry, ALPHA specifies the scalar alpha. */
+/* Unchanged on exit. */
+
+/* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). */
+/* Before entry with UPLO = 'U' or 'u', the leading n by n */
+/* upper triangular part of the array A must contain the upper */
+/* triangular part of the symmetric matrix and the strictly */
+/* lower triangular part of A is not referenced. */
+/* Before entry with UPLO = 'L' or 'l', the leading n by n */
+/* lower triangular part of the array A must contain the lower */
+/* triangular part of the symmetric matrix and the strictly */
+/* upper triangular part of A is not referenced. */
+/* Unchanged on exit. */
+
+/* LDA - INTEGER. */
+/* On entry, LDA specifies the first dimension of A as declared */
+/* in the calling (sub) program. LDA must be at least */
+/* max( 1, n ). */
+/* Unchanged on exit. */
+
+/* X - DOUBLE PRECISION array of dimension at least */
+/* ( 1 + ( n - 1 )*abs( INCX ) ). */
+/* Before entry, the incremented array X must contain the n */
+/* element vector x. */
+/* Unchanged on exit. */
+
+/* INCX - INTEGER. */
+/* On entry, INCX specifies the increment for the elements of */
+/* X. INCX must not be zero. */
+/* Unchanged on exit. */
+
+/* BETA - DOUBLE PRECISION. */
+/* On entry, BETA specifies the scalar beta. When BETA is */
+/* supplied as zero then Y need not be set on input. */
+/* Unchanged on exit. */
+
+/* Y - DOUBLE PRECISION array of dimension at least */
+/* ( 1 + ( n - 1 )*abs( INCY ) ). */
+/* Before entry, the incremented array Y must contain the n */
+/* element vector y. On exit, Y is overwritten by the updated */
+/* vector y. */
+
+/* INCY - INTEGER. */
+/* On entry, INCY specifies the increment for the elements of */
+/* Y. INCY must not be zero. */
+/* Unchanged on exit. */
+
+
+/* Level 2 Blas routine. */
+
+/* -- Written on 22-October-1986. */
+/* Jack Dongarra, Argonne National Lab. */
+/* Jeremy Du Croz, Nag Central Office. */
+/* Sven Hammarling, Nag Central Office. */
+/* Richard Hanson, Sandia National Labs. */
+
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+
+/* Test the input parameters. */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+ --x;
+ --y;
+
+ /* Function Body */
+ info = 0;
+ if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
+ info = 1;
+ } else if (*n < 0) {
+ info = 2;
+ } else if (*lda < max(1,*n)) {
+ info = 5;
+ } else if (*incx == 0) {
+ info = 7;
+ } else if (*incy == 0) {
+ info = 10;
+ }
+ if (info != 0) {
+ xerbla_("DSYMV ", &info);
+ return 0;
+ }
+
+/* Quick return if possible. */
+
+ if (*n == 0 || *alpha == 0. && *beta == 1.) {
+ return 0;
+ }
+
+/* Set up the start points in X and Y. */
+
+ if (*incx > 0) {
+ kx = 1;
+ } else {
+ kx = 1 - (*n - 1) * *incx;
+ }
+ if (*incy > 0) {
+ ky = 1;
+ } else {
+ ky = 1 - (*n - 1) * *incy;
+ }
+
+/* Start the operations. In this version the elements of A are */
+/* accessed sequentially with one pass through the triangular part */
+/* of A. */
+
+/* First form y := beta*y. */
+
+ if (*beta != 1.) {
+ if (*incy == 1) {
+ if (*beta == 0.) {
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ y[i__] = 0.;
+/* L10: */
+ }
+ } else {
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ y[i__] = *beta * y[i__];
+/* L20: */
+ }
+ }
+ } else {
+ iy = ky;
+ if (*beta == 0.) {
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ y[iy] = 0.;
+ iy += *incy;
+/* L30: */
+ }
+ } else {
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ y[iy] = *beta * y[iy];
+ iy += *incy;
+/* L40: */
+ }
+ }
+ }
+ }
+ if (*alpha == 0.) {
+ return 0;
+ }
+ if (lsame_(uplo, "U")) {
+
+/* Form y when A is stored in upper triangle. */
+
+ if (*incx == 1 && *incy == 1) {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ temp1 = *alpha * x[j];
+ temp2 = 0.;
+ i__2 = j - 1;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+ y[i__] += temp1 * a[i__ + j * a_dim1];
+ temp2 += a[i__ + j * a_dim1] * x[i__];
+/* L50: */
+ }
+ y[j] = y[j] + temp1 * a[j + j * a_dim1] + *alpha * temp2;
+/* L60: */
+ }
+ } else {
+ jx = kx;
+ jy = ky;
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ temp1 = *alpha * x[jx];
+ temp2 = 0.;
+ ix = kx;
+ iy = ky;
+ i__2 = j - 1;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+ y[iy] += temp1 * a[i__ + j * a_dim1];
+ temp2 += a[i__ + j * a_dim1] * x[ix];
+ ix += *incx;
+ iy += *incy;
+/* L70: */
+ }
+ y[jy] = y[jy] + temp1 * a[j + j * a_dim1] + *alpha * temp2;
+ jx += *incx;
+ jy += *incy;
+/* L80: */
+ }
+ }
+ } else {
+
+/* Form y when A is stored in lower triangle. */
+
+ if (*incx == 1 && *incy == 1) {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ temp1 = *alpha * x[j];
+ temp2 = 0.;
+ y[j] += temp1 * a[j + j * a_dim1];
+ i__2 = *n;
+ for (i__ = j + 1; i__ <= i__2; ++i__) {
+ y[i__] += temp1 * a[i__ + j * a_dim1];
+ temp2 += a[i__ + j * a_dim1] * x[i__];
+/* L90: */
+ }
+ y[j] += *alpha * temp2;
+/* L100: */
+ }
+ } else {
+ jx = kx;
+ jy = ky;
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ temp1 = *alpha * x[jx];
+ temp2 = 0.;
+ y[jy] += temp1 * a[j + j * a_dim1];
+ ix = jx;
+ iy = jy;
+ i__2 = *n;
+ for (i__ = j + 1; i__ <= i__2; ++i__) {
+ ix += *incx;
+ iy += *incy;
+ y[iy] += temp1 * a[i__ + j * a_dim1];
+ temp2 += a[i__ + j * a_dim1] * x[ix];
+/* L110: */
+ }
+ y[jy] += *alpha * temp2;
+ jx += *incx;
+ jy += *incy;
+/* L120: */
+ }
+ }
+ }
+
+ return 0;
+
+/* End of DSYMV . */
+
+} /* dsymv_ */
projects / opencv / blobdiff