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

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4.6 KiB
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/* fortran/zaxpy.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 ZAXPY */
/* =========== DOCUMENTATION =========== */
/* Online html documentation available at */
/* http://www.netlib.org/lapack/explore-html/ */
/* Definition: */
/* =========== */
/* SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY) */
/* .. Scalar Arguments .. */
/* COMPLEX*16 ZA */
/* INTEGER INCX,INCY,N */
/* .. */
/* .. Array Arguments .. */
/* COMPLEX*16 ZX(*),ZY(*) */
/* .. */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > ZAXPY constant times a vector plus a vector. */
/* > \endverbatim */
/* Arguments: */
/* ========== */
/* > \param[in] N */
/* > \verbatim */
/* > N is INTEGER */
/* > number of elements in input vector(s) */
/* > \endverbatim */
/* > */
/* > \param[in] ZA */
/* > \verbatim */
/* > ZA is COMPLEX*16 */
/* > On entry, ZA specifies the scalar alpha. */
/* > \endverbatim */
/* > */
/* > \param[in] ZX */
/* > \verbatim */
/* > ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) ) */
/* > \endverbatim */
/* > */
/* > \param[in] INCX */
/* > \verbatim */
/* > INCX is INTEGER */
/* > storage spacing between elements of ZX */
/* > \endverbatim */
/* > */
/* > \param[in,out] ZY */
/* > \verbatim */
/* > ZY is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCY ) ) */
/* > \endverbatim */
/* > */
/* > \param[in] INCY */
/* > \verbatim */
/* > INCY is INTEGER */
/* > storage spacing between elements of ZY */
/* > \endverbatim */
/* Authors: */
/* ======== */
/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */
/* > \ingroup complex16_blas_level1 */
/* > \par Further Details: */
/* ===================== */
/* > */
/* > \verbatim */
/* > */
/* > jack dongarra, 3/11/78. */
/* > modified 12/3/93, array(1) declarations changed to array(*) */
/* > \endverbatim */
/* > */
/* ===================================================================== */
/* Subroutine */ int zaxpy_(integer *n, doublecomplex *za, doublecomplex *zx,
integer *incx, doublecomplex *zy, integer *incy)
{
/* System generated locals */
integer i__1, i__2, i__3, i__4;
doublecomplex z__1, z__2;
/* Local variables */
integer i__, ix, iy;
extern doublereal dcabs1_(doublecomplex *);
/* -- Reference BLAS level1 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 .. */
/* .. */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* Parameter adjustments */
--zy;
--zx;
/* Function Body */
if (*n <= 0) {
return 0;
}
if (dcabs1_(za) == 0.) {
return 0;
}
if (*incx == 1 && *incy == 1) {
/* code for both increments equal to 1 */
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = i__;
i__3 = i__;
i__4 = i__;
z__2.r = za->r * zx[i__4].r - za->i * zx[i__4].i, z__2.i = za->r *
zx[i__4].i + za->i * zx[i__4].r;
z__1.r = zy[i__3].r + z__2.r, z__1.i = zy[i__3].i + z__2.i;
zy[i__2].r = z__1.r, zy[i__2].i = z__1.i;
}
} else {
/* code for unequal increments or equal increments */
/* not equal to 1 */
ix = 1;
iy = 1;
if (*incx < 0) {
ix = (-(*n) + 1) * *incx + 1;
}
if (*incy < 0) {
iy = (-(*n) + 1) * *incy + 1;
}
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = iy;
i__3 = iy;
i__4 = ix;
z__2.r = za->r * zx[i__4].r - za->i * zx[i__4].i, z__2.i = za->r *
zx[i__4].i + za->i * zx[i__4].r;
z__1.r = zy[i__3].r + z__2.r, z__1.i = zy[i__3].i + z__2.i;
zy[i__2].r = z__1.r, zy[i__2].i = z__1.i;
ix += *incx;
iy += *incy;
}
}
return 0;
/* End of ZAXPY */
} /* zaxpy_ */
#ifdef __cplusplus
}
#endif