# scasum.f

          FUNCTION SCASUM (N, CX, INCX)
    C***BEGIN PROLOGUE  SCASUM
    C***PURPOSE  Compute the sum of the magnitudes of the real and
    C            imaginary elements of a complex vector.
    C***LIBRARY   SLATEC (BLAS)
    C***CATEGORY  D1A3A
    C***TYPE      COMPLEX (SASUM-S, DASUM-D, SCASUM-C)
    C***KEYWORDS  BLAS, LINEAR ALGEBRA, SUM OF MAGNITUDES OF A VECTOR
    C***AUTHOR  Lawson, C. L., (JPL)
    C           Hanson, R. J., (SNLA)
    C           Kincaid, D. R., (U. of Texas)
    C           Krogh, F. T., (JPL)
    C***DESCRIPTION
    C
    C                B L A S  Subprogram
    C    Description of Parameters
    C
    C     --Input--
    C        N  number of elements in input vector(s)
    C       CX  complex vector with N elements
    C     INCX  storage spacing between elements of CX
    C
    C     --Output--
    C   SCASUM  single precision result (zero if N .LE. 0)
    C
    C     Returns sums of magnitudes of real and imaginary parts of
    C     components of CX.  Note that this is not the L1 norm of CX.
    C     CASUM = sum from 0 to N-1 of ABS(REAL(CX(IX+I*INCX))) +
    C             ABS(IMAG(CX(IX+I*INCX))),
    C     where IX = 1 if INCX .GE. 0, else IX = 1+(1-N)*INCX.
    C
    C***REFERENCES  C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.
    C                 Krogh, Basic linear algebra subprograms for Fortran
    C                 usage, Algorithm No. 539, Transactions on Mathematical
    C                 Software 5, 3 (September 1979), pp. 308-323.
    C***ROUTINES CALLED  (NONE)
    C***REVISION HISTORY  (YYMMDD)
    C   791001  DATE WRITTEN
    C   890831  Modified array declarations.  (WRB)
    C   890831  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C   900821  Modified to correct problem with a negative increment.
    C           (WRB)
    C   920501  Reformatted the REFERENCES section.  (WRB)
    C***END PROLOGUE  SCASUM