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