DPCHST(3)

SYNOPSIS
DOUBLE PRECISION FUNCTION DPCHST (ARG1, ARG2)

NAME
dpchst - DPCHIP Sign-Testing Routine

LIBRARY
SLATEC (PCHIP)

TYPE
DOUBLE PRECISION (PCHST-S, DPCHST-D)

AUTHOR
Fritsch, F. N., (LLNL)

DESCRIPTION
DPCHST: DPCHIP Sign-Testing Routine. Returns: -1. if ARG1 and ARG2 are of opposite sign. 0. if either argument is zero. +1. if ARG1 and ARG2 are of the same sign. The object is to do this without multiplying ARG1*ARG2, to avoid possible over/underflow problems. Fortran intrinsics used: SIGN.

SEE ALSO
DPCHCE, DPCHCI, DPCHCS, DPCHIM

ROUTINES CALLED
(NONE)

REVISION HISTORY (YYMMDD)
811103 DATE WRITTEN
820805 Converted to SLATEC library version.
870813 Minor cosmetic changes.
890411 Added SAVE statements (Vers. 3.2).
890531 Changed all specific intrinsics to generic. (WRB)
890531 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900328 Added TYPE section. (WRB)
910408 Updated AUTHOR and DATE WRITTEN sections in prologue. (WRB)
930503 Improved purpose. (FNF)