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Annotation of rpl/lapack/blas/zaxpy.f, revision 1.15

1.8       bertrand    1: *> \brief \b ZAXPY
                      2: *
                      3: *  =========== DOCUMENTATION ===========
                      4: *
1.13      bertrand    5: * Online html documentation available at
                      6: *            http://www.netlib.org/lapack/explore-html/
1.8       bertrand    7: *
                      8: *  Definition:
                      9: *  ===========
                     10: *
                     11: *       SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
1.13      bertrand   12: *
1.8       bertrand   13: *       .. Scalar Arguments ..
                     14: *       COMPLEX*16 ZA
                     15: *       INTEGER INCX,INCY,N
                     16: *       ..
                     17: *       .. Array Arguments ..
                     18: *       COMPLEX*16 ZX(*),ZY(*)
                     19: *       ..
1.13      bertrand   20: *
1.8       bertrand   21: *
                     22: *> \par Purpose:
                     23: *  =============
                     24: *>
                     25: *> \verbatim
                     26: *>
                     27: *>    ZAXPY constant times a vector plus a vector.
                     28: *> \endverbatim
                     29: *
1.14      bertrand   30: *  Arguments:
                     31: *  ==========
                     32: *
                     33: *> \param[in] N
                     34: *> \verbatim
                     35: *>          N is INTEGER
                     36: *>         number of elements in input vector(s)
                     37: *> \endverbatim
                     38: *>
                     39: *> \param[in] ZA
                     40: *> \verbatim
                     41: *>          ZA is COMPLEX*16
                     42: *>           On entry, ZA specifies the scalar alpha.
                     43: *> \endverbatim
                     44: *>
                     45: *> \param[in] ZX
                     46: *> \verbatim
                     47: *>          ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
                     48: *> \endverbatim
                     49: *>
                     50: *> \param[in] INCX
                     51: *> \verbatim
                     52: *>          INCX is INTEGER
                     53: *>         storage spacing between elements of ZX
                     54: *> \endverbatim
                     55: *>
                     56: *> \param[in,out] ZY
                     57: *> \verbatim
                     58: *>          ZY is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
                     59: *> \endverbatim
                     60: *>
                     61: *> \param[in] INCY
                     62: *> \verbatim
                     63: *>          INCY is INTEGER
                     64: *>         storage spacing between elements of ZY
                     65: *> \endverbatim
                     66: *
1.8       bertrand   67: *  Authors:
                     68: *  ========
                     69: *
1.13      bertrand   70: *> \author Univ. of Tennessee
                     71: *> \author Univ. of California Berkeley
                     72: *> \author Univ. of Colorado Denver
                     73: *> \author NAG Ltd.
1.8       bertrand   74: *
1.14      bertrand   75: *> \date November 2017
1.8       bertrand   76: *
                     77: *> \ingroup complex16_blas_level1
                     78: *
                     79: *> \par Further Details:
                     80: *  =====================
                     81: *>
                     82: *> \verbatim
                     83: *>
                     84: *>     jack dongarra, 3/11/78.
                     85: *>     modified 12/3/93, array(1) declarations changed to array(*)
                     86: *> \endverbatim
                     87: *>
                     88: *  =====================================================================
1.1       bertrand   89:       SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
1.8       bertrand   90: *
1.14      bertrand   91: *  -- Reference BLAS level1 routine (version 3.8.0) --
1.8       bertrand   92: *  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
                     93: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.14      bertrand   94: *     November 2017
1.8       bertrand   95: *
1.1       bertrand   96: *     .. Scalar Arguments ..
1.8       bertrand   97:       COMPLEX*16 ZA
1.1       bertrand   98:       INTEGER INCX,INCY,N
                     99: *     ..
                    100: *     .. Array Arguments ..
1.8       bertrand  101:       COMPLEX*16 ZX(*),ZY(*)
1.1       bertrand  102: *     ..
                    103: *
                    104: *  =====================================================================
                    105: *
                    106: *     .. Local Scalars ..
                    107:       INTEGER I,IX,IY
                    108: *     ..
                    109: *     .. External Functions ..
                    110:       DOUBLE PRECISION DCABS1
                    111:       EXTERNAL DCABS1
                    112: *     ..
                    113:       IF (N.LE.0) RETURN
                    114:       IF (DCABS1(ZA).EQ.0.0d0) RETURN
1.7       bertrand  115:       IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
                    116: *
                    117: *        code for both increments equal to 1
                    118: *
                    119:          DO I = 1,N
                    120:             ZY(I) = ZY(I) + ZA*ZX(I)
                    121:          END DO
                    122:       ELSE
1.1       bertrand  123: *
                    124: *        code for unequal increments or equal increments
                    125: *          not equal to 1
                    126: *
1.7       bertrand  127:          IX = 1
                    128:          IY = 1
                    129:          IF (INCX.LT.0) IX = (-N+1)*INCX + 1
                    130:          IF (INCY.LT.0) IY = (-N+1)*INCY + 1
                    131:          DO I = 1,N
                    132:             ZY(IY) = ZY(IY) + ZA*ZX(IX)
                    133:             IX = IX + INCX
                    134:             IY = IY + INCY
                    135:          END DO
                    136:       END IF
1.1       bertrand  137: *
                    138:       RETURN
                    139:       END