dpchkt.f
SUBROUTINE DPCHKT (N, X, KNOTYP, T)
C***BEGIN PROLOGUE DPCHKT
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Compute B-spline knot sequence for DPCHBS.
C***LIBRARY SLATEC (PCHIP)
C***CATEGORY E3
C***TYPE DOUBLE PRECISION (PCHKT-S, DPCHKT-D)
C***AUTHOR Fritsch, F. N., (LLNL)
C***DESCRIPTION
C
C Set a knot sequence for the B-spline representation of a PCH
C function with breakpoints X. All knots will be at least double.
C Endknots are set as:
C (1) quadruple knots at endpoints if KNOTYP=0;
C (2) extrapolate the length of end interval if KNOTYP=1;
C (3) periodic if KNOTYP=2.
C
C Input arguments: N, X, KNOTYP.
C Output arguments: T.
C
C Restrictions/assumptions:
C 1. N.GE.2 . (not checked)
C 2. X(i).LT.X(i+1), i=1,...,N . (not checked)
C 3. 0.LE.KNOTYP.LE.2 . (Acts like KNOTYP=0 for any other value.)
C
C***SEE ALSO DPCHBS
C***ROUTINES CALLED (NONE)
C***REVISION HISTORY (YYMMDD)
C 870701 DATE WRITTEN
C 900405 Converted Fortran to upper case.
C 900410 Converted prologue to SLATEC 4.0 format.
C 900410 Minor cosmetic changes.
C 900430 Produced double precision version.
C 930514 Changed NKNOTS from an output to an input variable. (FNF)
C 930604 Removed unused variable NKNOTS from argument list. (FNF)
C***END PROLOGUE DPCHKT