PCHCE(3)

SYNOPSIS
SUBROUTINE PCHCE (IC, VC, N, X, H, SLOPE, D, INCFD, IERR)

NAME
pchce - Set boundary conditions for PCHIC

LIBRARY
SLATEC (PCHIP)

TYPE
SINGLE PRECISION (PCHCE-S, DPCHCE-D)

AUTHOR
Fritsch, F. N., (LLNL)

DESCRIPTION
PCHCE: PCHIC End Derivative Setter. Called by PCHIC to set end derivatives as requested by the user. It must be called after interior derivative values have been set. ----- To facilitate two-dimensional applications, includes an increment between successive values of the D-array. ---------------------------------------------------------------------- Calling sequence: PARAMETER (INCFD = ...) INTEGER IC(2), N, IERR REAL VC(2), X(N), H(N), SLOPE(N), D(INCFD,N) CALL PCHCE (IC, VC, N, X, H, SLOPE, D, INCFD, IERR) Parameters: IC -- (input) integer array of length 2 specifying desired boundary conditions: IC(1) = IBEG, desired condition at beginning of data. IC(2) = IEND, desired condition at end of data. ( see prologue to PCHIC for details. ) VC -- (input) real array of length 2 specifying desired boundary values. VC(1) need be set only if IC(1) = 2 or 3 . VC(2) need be set only if IC(2) = 2 or 3 . N -- (input) number of data points. (assumes N.GE.2) X -- (input) real array of independent variable values. (the elements of X are assumed to be strictly increasing.) H -- (input) real array of interval lengths. SLOPE -- (input) real array of data slopes. If the data are (X(I),Y(I)), I=1(1)N, then these inputs are: H(I) = X(I+1)-X(I), SLOPE(I) = (Y(I+1)-Y(I))/H(I), I=1(1)N-1. D -- (input) real array of derivative values at the data points. The value corresponding to X(I) must be stored in D(1+(I-1)*INCFD), I=1(1)N. (output) the value of D at X(1) and/or X(N) is changed, if necessary, to produce the requested boundary conditions. no other entries in D are changed. INCFD -- (input) increment between successive values in D. This argument is provided primarily for 2-D applications. IERR -- (output) error flag. Normal return: IERR = 0 (no errors). Warning errors: IERR = 1 if IBEG.LT.0 and D(1) had to be adjusted for monotonicity. IERR = 2 if IEND.LT.0 and D(1+(N-1)*INCFD) had to be adjusted for monotonicity. IERR = 3 if both of the above are true. ------- WARNING: This routine does no validity-checking of arguments. ------- Fortran intrinsics used: ABS.

SEE ALSO
PCHIC

ROUTINES CALLED
PCHDF, PCHST, XERMSG

REVISION HISTORY (YYMMDD)
820218 DATE WRITTEN
820805 Converted to SLATEC library version.
870707 Minor corrections made to prologue..
890411 Added SAVE statements (Vers. 3.2).
890531 Changed all specific intrinsics to generic. (WRB)
890831 Modified array declarations. (WRB)
890831 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
900328 Added TYPE section. (WRB)
910408 Updated AUTHOR section in prologue. (WRB)
930503 Improved purpose. (FNF)