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    1: *> \brief \b DZASUM
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *  Definition:
    9: *  ===========
   10: *
   11: *       DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
   12: *
   13: *       .. Scalar Arguments ..
   14: *       INTEGER INCX,N
   15: *       ..
   16: *       .. Array Arguments ..
   17: *       COMPLEX*16 ZX(*)
   18: *       ..
   19: *
   20: *
   21: *> \par Purpose:
   22: *  =============
   23: *>
   24: *> \verbatim
   25: *>
   26: *>    DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
   27: *>    returns a single precision result.
   28: *> \endverbatim
   29: *
   30: *  Authors:
   31: *  ========
   32: *
   33: *> \author Univ. of Tennessee
   34: *> \author Univ. of California Berkeley
   35: *> \author Univ. of Colorado Denver
   36: *> \author NAG Ltd.
   37: *
   38: *> \date December 2016
   39: *
   40: *> \ingroup double_blas_level1
   41: *
   42: *> \par Further Details:
   43: *  =====================
   44: *>
   45: *> \verbatim
   46: *>
   47: *>     jack dongarra, 3/11/78.
   48: *>     modified 3/93 to return if incx .le. 0.
   49: *>     modified 12/3/93, array(1) declarations changed to array(*)
   50: *> \endverbatim
   51: *>
   52: *  =====================================================================
   53:       DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
   54: *
   55: *  -- Reference BLAS level1 routine (version 3.7.0) --
   56: *  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
   57: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   58: *     December 2016
   59: *
   60: *     .. Scalar Arguments ..
   61:       INTEGER INCX,N
   62: *     ..
   63: *     .. Array Arguments ..
   64:       COMPLEX*16 ZX(*)
   65: *     ..
   66: *
   67: *  =====================================================================
   68: *
   69: *     .. Local Scalars ..
   70:       DOUBLE PRECISION STEMP
   71:       INTEGER I,NINCX
   72: *     ..
   73: *     .. External Functions ..
   74:       DOUBLE PRECISION DCABS1
   75:       EXTERNAL DCABS1
   76: *     ..
   77:       DZASUM = 0.0d0
   78:       STEMP = 0.0d0
   79:       IF (N.LE.0 .OR. INCX.LE.0) RETURN
   80:       IF (INCX.EQ.1) THEN
   81: *
   82: *        code for increment equal to 1
   83: *
   84:          DO I = 1,N
   85:             STEMP = STEMP + DCABS1(ZX(I))
   86:          END DO
   87:       ELSE
   88: *
   89: *        code for increment not equal to 1
   90: *
   91:          NINCX = N*INCX
   92:          DO I = 1,NINCX,INCX
   93:             STEMP = STEMP + DCABS1(ZX(I))
   94:          END DO
   95:       END IF
   96:       DZASUM = STEMP
   97:       RETURN
   98:       END