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Annotation of rpl/lapack/blas/dzasum.f, revision 1.17

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
1.17    ! bertrand   27: *>    returns a double 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: *
                     58: *> \ingroup double_blas_level1
                     59: *
                     60: *> \par Further Details:
                     61: *  =====================
                     62: *>
                     63: *> \verbatim
                     64: *>
                     65: *>     jack dongarra, 3/11/78.
                     66: *>     modified 3/93 to return if incx .le. 0.
                     67: *>     modified 12/3/93, array(1) declarations changed to array(*)
                     68: *> \endverbatim
                     69: *>
                     70: *  =====================================================================
1.1       bertrand   71:       DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.8       bertrand   72: *
1.17    ! bertrand   73: *  -- Reference BLAS level1 routine --
1.8       bertrand   74: *  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
                     75: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
                     76: *
1.1       bertrand   77: *     .. Scalar Arguments ..
                     78:       INTEGER INCX,N
                     79: *     ..
                     80: *     .. Array Arguments ..
1.8       bertrand   81:       COMPLEX*16 ZX(*)
1.1       bertrand   82: *     ..
                     83: *
                     84: *  =====================================================================
                     85: *
                     86: *     .. Local Scalars ..
                     87:       DOUBLE PRECISION STEMP
1.7       bertrand   88:       INTEGER I,NINCX
1.1       bertrand   89: *     ..
                     90: *     .. External Functions ..
                     91:       DOUBLE PRECISION DCABS1
                     92:       EXTERNAL DCABS1
                     93: *     ..
                     94:       DZASUM = 0.0d0
                     95:       STEMP = 0.0d0
                     96:       IF (N.LE.0 .OR. INCX.LE.0) RETURN
1.7       bertrand   97:       IF (INCX.EQ.1) THEN
1.1       bertrand   98: *
1.7       bertrand   99: *        code for increment equal to 1
1.1       bertrand  100: *
1.7       bertrand  101:          DO I = 1,N
                    102:             STEMP = STEMP + DCABS1(ZX(I))
                    103:          END DO
                    104:       ELSE
1.1       bertrand  105: *
1.7       bertrand  106: *        code for increment not equal to 1
1.1       bertrand  107: *
1.7       bertrand  108:          NINCX = N*INCX
                    109:          DO I = 1,NINCX,INCX
                    110:             STEMP = STEMP + DCABS1(ZX(I))
                    111:          END DO
                    112:       END IF
1.1       bertrand  113:       DZASUM = STEMP
                    114:       RETURN
1.17    ! bertrand  115: *
        !           116: *     End of DZASUM
        !           117: *
1.1       bertrand  118:       END