# dcopym.f

          SUBROUTINE DCOPYM (N, DX, INCX, DY, INCY)
    C***BEGIN PROLOGUE  DCOPYM
    C***PURPOSE  Copy the negative of a vector to a vector.
    C***LIBRARY   SLATEC (BLAS)
    C***CATEGORY  D1A5
    C***TYPE      DOUBLE PRECISION (SCOPYM-S, DCOPYM-D)
    C***KEYWORDS  BLAS, COPY, VECTOR
    C***AUTHOR  Kahaner, D. K., (NBS)
    C***DESCRIPTION
    C
    C       Description of Parameters
    C           The * Flags Output Variables
    C
    C       N   Number of elements in vector(s)
    C      DX   Double precision vector with N elements
    C    INCX   Storage spacing between elements of DX
    C      DY*  Double precision negative copy of DX
    C    INCY   Storage spacing between elements of DY
    C
    C      ***  Note that DY = -DX  ***
    C
    C     Copy negative of d.p. DX to d.p. DY.  For I=0 to N-1,
    C     copy  -DX(LX+I*INCX) to DY(LY+I*INCY), where LX=1 if
    C     INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is defined
    C     in a similar way using INCY.
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  (NONE)
    C***REVISION HISTORY  (YYMMDD)
    C   801001  DATE WRITTEN
    C   861211  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C   920310  Corrected definition of LX in DESCRIPTION.  (WRB)
    C***END PROLOGUE  DCOPYM