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lammps/lib/linalg/dger.cpp
2022-12-28 13:18:38 -05:00

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/* fortran/dger.f -- translated by f2c (version 20200916).
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
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
/* > \brief \b DGER */
/* =========== DOCUMENTATION =========== */
/* Online html documentation available at */
/* http://www.netlib.org/lapack/explore-html/ */
/* Definition: */
/* =========== */
/* SUBROUTINE DGER(M,N,ALPHA,X,INCX,Y,INCY,A,LDA) */
/* .. Scalar Arguments .. */
/* DOUBLE PRECISION ALPHA */
/* INTEGER INCX,INCY,LDA,M,N */
/* .. */
/* .. Array Arguments .. */
/* DOUBLE PRECISION A(LDA,*),X(*),Y(*) */
/* .. */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > DGER performs the rank 1 operation */
/* > */
/* > A := alpha*x*y**T + A, */
/* > */
/* > where alpha is a scalar, x is an m element vector, y is an n element */
/* > vector and A is an m by n matrix. */
/* > \endverbatim */
/* Arguments: */
/* ========== */
/* > \param[in] M */
/* > \verbatim */
/* > M is INTEGER */
/* > On entry, M specifies the number of rows of the matrix A. */
/* > M must be at least zero. */
/* > \endverbatim */
/* > */
/* > \param[in] N */
/* > \verbatim */
/* > N is INTEGER */
/* > On entry, N specifies the number of columns 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] X */
/* > \verbatim */
/* > X is DOUBLE PRECISION array, dimension at least */
/* > ( 1 + ( m - 1 )*abs( INCX ) ). */
/* > Before entry, the incremented array X must contain the m */
/* > 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] 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. */
/* > \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 */
/* > */
/* > \param[in,out] A */
/* > \verbatim */
/* > A is DOUBLE PRECISION array, dimension ( LDA, N ) */
/* > Before entry, the leading m by n part of the array A must */
/* > contain the matrix of coefficients. On exit, A is */
/* > overwritten by the updated matrix. */
/* > \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, m ). */
/* > \endverbatim */
/* Authors: */
/* ======== */
/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */
/* > \ingroup double_blas_level2 */
/* > \par Further Details: */
/* ===================== */
/* > */
/* > \verbatim */
/* > */
/* > 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. */
/* > \endverbatim */
/* > */
/* ===================================================================== */
/* Subroutine */ int dger_(integer *m, integer *n, doublereal *alpha,
doublereal *x, integer *incx, doublereal *y, integer *incy,
doublereal *a, integer *lda)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
/* Local variables */
integer i__, j, ix, jy, kx, info;
doublereal temp;
extern /* Subroutine */ int xerbla_(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..-- */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* Test the input parameters. */
/* Parameter adjustments */
--x;
--y;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
/* Function Body */
info = 0;
if (*m < 0) {
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,*m)) {
info = 9;
}
if (info != 0) {
xerbla_((char *)"DGER ", &info, (ftnlen)6);
return 0;
}
/* Quick return if possible. */
if (*m == 0 || *n == 0 || *alpha == 0.) {
return 0;
}
/* Start the operations. In this version the elements of A are */
/* accessed sequentially with one pass through A. */
if (*incy > 0) {
jy = 1;
} else {
jy = 1 - (*n - 1) * *incy;
}
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (y[jy] != 0.) {
temp = *alpha * y[jy];
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] += x[i__] * temp;
/* L10: */
}
}
jy += *incy;
/* L20: */
}
} else {
if (*incx > 0) {
kx = 1;
} else {
kx = 1 - (*m - 1) * *incx;
}
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (y[jy] != 0.) {
temp = *alpha * y[jy];
ix = kx;
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] += x[ix] * temp;
ix += *incx;
/* L30: */
}
}
jy += *incy;
/* L40: */
}
}
return 0;
/* End of DGER */
} /* dger_ */
#ifdef __cplusplus
}
#endif