BLAS/src/single/csscal.c

110 lines
2.4 KiB
C

#include <complex.h>
/*
*> \brief \b CSSCAL
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* SUBROUTINE CSSCAL(N,SA,CX,INCX)
*
* .. Scalar Arguments ..
* REAL SA
* INTEGER INCX,N
* ..
* .. Array Arguments ..
* COMPLEX CX(*)
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CSSCAL scales a complex vector by a real constant.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> number of elements in input vector(s)
*> \endverbatim
*>
*> \param[in] SA
*> \verbatim
*> SA is REAL
*> On entry, SA specifies the scalar alpha.
*> \endverbatim
*>
*> \param[in,out] CX
*> \verbatim
*> CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> storage spacing between elements of CX
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \ingroup complex_blas_level1
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> jack dongarra, linpack, 3/11/78.
*> modified 3/93 to return if incx .le. 0.
*> modified 12/3/93, array(1) declarations changed to array(*)
*> \endverbatim
*>
* =====================================================================
*/
void csscal(int n, float sa, complex float *cx, int incx) {
// -- 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..--
// =====================================================================
// .. Local Scalars ..
int i, nincx;
float one = 1.0;
if (n <= 0 || incx <= 0 || sa == one) return;
if (incx == 1) {
// code for increment equal to 1
for (i = 0; i < n; i++) {
cx[i] = sa * creal(cx[i]) + sa * cimag(cx[i]) * I;
}
} else {
// code for increment not equal to 1
nincx = n * incx;
for (i = 0; i < nincx; i += incx) {
cx[i] = sa * creal(cx[i]) + sa * cimag(cx[i]) * I;
}
}
// End of CSSCAL
}