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agent_compositor_test/references/igraph-1.0.1/vendor/lapack/dsymv.c
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/* -- translated by f2c (version 20240504).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
/* > \brief \b DSYMV
=========== DOCUMENTATION ===========
Online html documentation available at
http://www.netlib.org/lapack/explore-html/
Definition:
===========
SUBROUTINE DSYMV(UPLO,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
DOUBLE PRECISION ALPHA,BETA
INTEGER INCX,INCY,LDA,N
CHARACTER UPLO
DOUBLE PRECISION A(LDA,*),X(*),Y(*)
> \par Purpose:
=============
>
> \verbatim
>
> 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.
> \endverbatim
Arguments:
==========
> \param[in] UPLO
> \verbatim
> UPLO is 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.
> \endverbatim
>
> \param[in] N
> \verbatim
> N is INTEGER
> On entry, N specifies the order of the matrix A.
> N must be at least zero.
> \endverbatim
>
> \param[in] ALPHA
> \verbatim
> ALPHA is DOUBLE PRECISION.
> On entry, ALPHA specifies the scalar alpha.
> \endverbatim
>
> \param[in] A
> \verbatim
> A is DOUBLE PRECISION array, 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.
> \endverbatim
>
> \param[in] LDA
> \verbatim
> LDA is 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 ).
> \endverbatim
>
> \param[in] X
> \verbatim
> X is DOUBLE PRECISION array, dimension at least
> ( 1 + ( n - 1 )*abs( INCX ) ).
> Before entry, the incremented array X must contain the n
> element vector x.
> \endverbatim
>
> \param[in] INCX
> \verbatim
> INCX is INTEGER
> On entry, INCX specifies the increment for the elements of
> X. INCX must not be zero.
> \endverbatim
>
> \param[in] BETA
> \verbatim
> BETA is DOUBLE PRECISION.
> On entry, BETA specifies the scalar beta. When BETA is
> supplied as zero then Y need not be set on input.
> \endverbatim
>
> \param[in,out] Y
> \verbatim
> Y is DOUBLE PRECISION array, 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.
> \endverbatim
>
> \param[in] INCY
> \verbatim
> INCY is INTEGER
> On entry, INCY specifies the increment for the elements of
> Y. INCY must not be zero.
> \endverbatim
Authors:
========
> \author Univ. of Tennessee
> \author Univ. of California Berkeley
> \author Univ. of Colorado Denver
> \author NAG Ltd.
> \ingroup hemv
> \par Further Details:
=====================
>
> \verbatim
>
> Level 2 Blas routine.
> The vector and matrix arguments are not referenced when N = 0, or M = 0
>
> -- 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.
> \endverbatim
>
=====================================================================
Subroutine */ int igraphdsymv_(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 igraphlsame_(char *, char *);
extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
/* -- Reference BLAS level2 routine --
-- Reference BLAS is a software package provided by Univ. of Tennessee, --
-- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
=====================================================================
Test the input parameters.
Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--x;
--y;
/* Function Body */
info = 0;
if (! igraphlsame_(uplo, "U") && ! igraphlsame_(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) {
igraphxerbla_("DSYMV ", &info, (ftnlen)6);
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 (igraphlsame_(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 */
} /* igraphdsymv_ */
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