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Annotation of rpl/lapack/blas/dzasum.f, revision 1.16

1.8       bertrand    1: *> \brief \b DZASUM
                      2: *
                      3: *  =========== DOCUMENTATION ===========
                      4: *
1.14      bertrand    5: * Online html documentation available at
                      6: *            http://www.netlib.org/lapack/explore-html/
1.8       bertrand    7: *
                      8: *  Definition:
                      9: *  ===========
                     10: *
                     11: *       DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.14      bertrand   12: *
1.8       bertrand   13: *       .. Scalar Arguments ..
                     14: *       INTEGER INCX,N
                     15: *       ..
                     16: *       .. Array Arguments ..
                     17: *       COMPLEX*16 ZX(*)
                     18: *       ..
1.14      bertrand   19: *
1.8       bertrand   20: *
                     21: *> \par Purpose:
                     22: *  =============
                     23: *>
                     24: *> \verbatim
                     25: *>
1.12      bertrand   26: *>    DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
                     27: *>    returns a single precision result.
1.8       bertrand   28: *> \endverbatim
                     29: *
1.15      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,out] ZX
                     40: *> \verbatim
                     41: *>          ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
                     42: *> \endverbatim
                     43: *>
                     44: *> \param[in] INCX
                     45: *> \verbatim
                     46: *>          INCX is INTEGER
                     47: *>         storage spacing between elements of ZX
                     48: *> \endverbatim
                     49: *
1.8       bertrand   50: *  Authors:
                     51: *  ========
                     52: *
1.14      bertrand   53: *> \author Univ. of Tennessee
                     54: *> \author Univ. of California Berkeley
                     55: *> \author Univ. of Colorado Denver
                     56: *> \author NAG Ltd.
1.8       bertrand   57: *
1.15      bertrand   58: *> \date November 2017
1.8       bertrand   59: *
                     60: *> \ingroup double_blas_level1
                     61: *
                     62: *> \par Further Details:
                     63: *  =====================
                     64: *>
                     65: *> \verbatim
                     66: *>
                     67: *>     jack dongarra, 3/11/78.
                     68: *>     modified 3/93 to return if incx .le. 0.
                     69: *>     modified 12/3/93, array(1) declarations changed to array(*)
                     70: *> \endverbatim
                     71: *>
                     72: *  =====================================================================
1.1       bertrand   73:       DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.8       bertrand   74: *
1.15      bertrand   75: *  -- Reference BLAS level1 routine (version 3.8.0) --
1.8       bertrand   76: *  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
                     77: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.15      bertrand   78: *     November 2017
1.8       bertrand   79: *
1.1       bertrand   80: *     .. Scalar Arguments ..
                     81:       INTEGER INCX,N
                     82: *     ..
                     83: *     .. Array Arguments ..
1.8       bertrand   84:       COMPLEX*16 ZX(*)
1.1       bertrand   85: *     ..
                     86: *
                     87: *  =====================================================================
                     88: *
                     89: *     .. Local Scalars ..
                     90:       DOUBLE PRECISION STEMP
1.7       bertrand   91:       INTEGER I,NINCX
1.1       bertrand   92: *     ..
                     93: *     .. External Functions ..
                     94:       DOUBLE PRECISION DCABS1
                     95:       EXTERNAL DCABS1
                     96: *     ..
                     97:       DZASUM = 0.0d0
                     98:       STEMP = 0.0d0
                     99:       IF (N.LE.0 .OR. INCX.LE.0) RETURN
1.7       bertrand  100:       IF (INCX.EQ.1) THEN
1.1       bertrand  101: *
1.7       bertrand  102: *        code for increment equal to 1
1.1       bertrand  103: *
1.7       bertrand  104:          DO I = 1,N
                    105:             STEMP = STEMP + DCABS1(ZX(I))
                    106:          END DO
                    107:       ELSE
1.1       bertrand  108: *
1.7       bertrand  109: *        code for increment not equal to 1
1.1       bertrand  110: *
1.7       bertrand  111:          NINCX = N*INCX
                    112:          DO I = 1,NINCX,INCX
                    113:             STEMP = STEMP + DCABS1(ZX(I))
                    114:          END DO
                    115:       END IF
1.1       bertrand  116:       DZASUM = STEMP
                    117:       RETURN
                    118:       END