DASUM(3)

SYNOPSIS
DOUBLE PRECISION FUNCTION DASUM (N, DX, INCX)

NAME
dasum - Compute the sum of the magnitudes of the elements of a vector.

LIBRARY
SLATEC (BLAS)

CATEGORY
D1A3A

TYPE
DOUBLE PRECISION (SASUM-S, DASUM-D, SCASUM-C)

KEYWORDS
BLAS, LINEAR ALGEBRA, SUM OF MAGNITUDES OF A VECTOR

AUTHOR
Lawson, C. L., (JPL) Hanson, R. J., (SNLA) Kincaid, D. R., (U. of Texas) Krogh, F. T., (JPL)

DESCRIPTION
B L A S Subprogram Description of Parameters --Input-- N number of elements in input vector(s) DX double precision vector with N elements INCX storage spacing between elements of DX --Output-- DASUM double precision result (zero if N .LE. 0) Returns sum of magnitudes of double precision DX. DASUM = sum from 0 to N-1 of ABS(DX(IX+I*INCX)), where IX = 1 if INCX .GE. 0, else IX = 1+(1-N)*INCX.

REFERENCES
C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T. Krogh, Basic linear algebra subprograms for Fortran usage, Algorithm No. 539, Transactions on Mathematical Software 5, 3 (September 1979), pp. 308-323.

ROUTINES CALLED
(NONE)

REVISION HISTORY (YYMMDD)
791001 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
890831 Modified array declarations. (WRB)
890831 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900821 Modified to correct problem with a negative increment. (WRB)
920501 Reformatted the REFERENCES section. (WRB)