*> \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 ZAXPY(N,ZA,ZX,INCX,ZY,INCY) * * -- 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 .. COMPLEX*16 ZA INTEGER INCX,INCY,N * .. * .. Array Arguments .. COMPLEX*16 ZX(*),ZY(*) * .. * * ===================================================================== * * .. Local Scalars .. INTEGER I,IX,IY * .. * .. External Functions .. DOUBLE PRECISION DCABS1 EXTERNAL DCABS1 * .. IF (N.LE.0) RETURN IF (DCABS1(ZA).EQ.0.0d0) RETURN IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN * * code for both increments equal to 1 * DO I = 1,N ZY(I) = ZY(I) + ZA*ZX(I) END DO ELSE * * code for unequal increments or equal increments * not equal to 1 * IX = 1 IY = 1 IF (INCX.LT.0) IX = (-N+1)*INCX + 1 IF (INCY.LT.0) IY = (-N+1)*INCY + 1 DO I = 1,N ZY(IY) = ZY(IY) + ZA*ZX(IX) IX = IX + INCX IY = IY + INCY END DO END IF * RETURN * * End of ZAXPY * END