PCHQK3(3)

SYNOPSIS
SUBROUTINE PCHQK3 (LUN, KPRINT, IPASS)

NAME
pchqk3 - Test the PCHIP interpolators PCHIC, PCHIM, PCHSP.

LIBRARY
SLATEC (PCHIP)

TYPE
SINGLE PRECISION (PCHQK3-S, DPCHQ3-D)

KEYWORDS
PCHIP INTERPOLATOR QUICK CHECK

AUTHOR
Fritsch, F. N., (LLNL)

DESCRIPTION
PCHIP QUICK CHECK NUMBER 3 TESTS THE INTERPOLATORS: PCHIC, PCHIM, PCHSP. *Usage: INTEGER LUN, KPRINT, IPASS CALL PCHQK3 (LUN, KPRINT, IPASS) *Arguments: LUN :IN is the unit number to which output is to be written. KPRINT:IN controls the amount of output, as specified in the SLATEC Guidelines. IPASS:OUT will contain a pass/fail flag. IPASS=1 is good. IPASS=0 indicates one or more tests failed. *Description: This routine interpolates a constructed data set with all three PCHIP interpolators and compares the results with those obtained on a Cray X/MP. Two different values of the PCHIC parameter SWITCH are used. *Remarks: 1. The Cray results are given only to nine significant figures, so don't expect them to match to more. 2. The results will depend to some extent on the accuracy of the EXP function.

ROUTINES CALLED
COMP, PCHIC, PCHIM, PCHSP, R1MACH

REVISION HISTORY (YYMMDD)
900309 DATE WRITTEN
900314 Converted to a subroutine and added a SLATEC 4.0 prologue.
900315 Revised prologue and improved some output formats. (FNF)
900316 Made TOLD machine-dependent and added extra output when KPRINT=3. (FNF)
900320 Added E0's to DATA statement for X to reduce single/double differences, and other minor cosmetic changes.
900321 Removed IFAIL from call sequence for SLATEC standards and made miscellaneous cosmetic changes. (FNF)
900322 Minor changes to reduce single/double differences. (FNF)
900530 Tolerance (TOLD) changed. (WRB)
900802 Modified TOLD formula and constants in PCHIC calls to be compatible with DPCHQ3. (FNF)
901130 Several significant changes: (FNF) 1. Changed comparison between PCHIM and PCHIC to only require agreement to machine precision. 2. Revised to print more output when KPRINT=3. 3. Added 1P's to formats.
910708 Minor modifications in use of KPRINT. (WRB)
930317 Improved output formats. (FNF)