BLAS/src/single/cdotu.c

119 lines
2.6 KiB
C

#include <complex.h>
/*
*> \brief \b CDOTU
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* COMPLEX FUNCTION CDOTU(N,CX,INCX,CY,INCY)
*
* .. Scalar Arguments ..
* INTEGER INCX,INCY,N
* ..
* .. Array Arguments ..
* COMPLEX CX(*),CY(*)
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CDOTU forms the dot product of two complex vectors
*> CDOTU = X^T * Y
*>
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> number of elements in input vector(s)
*> \endverbatim
*>
*> \param[in] 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
*>
*> \param[in] CY
*> \verbatim
*> CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
*> \endverbatim
*>
*> \param[in] INCY
*> \verbatim
*> INCY is INTEGER
*> storage spacing between elements of CY
*> \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 12/3/93, array(1) declarations changed to array(*)
*> \endverbatim
*>
* =====================================================================
*/
complex float cdotu(int n, complex float* cx, int incx, complex float *cy, int incy) {
// -- Reference BLAS level1 routine (version 3.4.0) --
// -- Reference BLAS is a software package provided by Univ. of Tennessee, --
// -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
// November 2011
int i, ix, iy;
complex double ctemp = 0.0 + 0.0*I;
if (n <= 0) return ctemp;
if (incx == 1 && incy == 1) {
// code for both increments equal to 1
for (i = 0; i < n; i++) {
ctemp += cx[i] * cy[i];
}
} else {
// code for unequal increments or equal increments not equal to 1
ix = 0;
iy = 0;
if (incx < 0) ix = (-n+1)*incx;
if (incy < 0) iy = (-n+1)*incy;
for (i = 0; i < n; i++) {
ctemp += cx[ix] * cy[iy];
ix += incx;
iy += incy;
}
}
return ctemp;
// End of CDOTU
}