DPOLCF(3)

SYNOPSIS
SUBROUTINE DPOLCF (XX, N, X, C, D, WORK)

NAME
dpolcf - Compute the coefficients of the polynomial fit (including Hermite polynomial fits) produced by a previous call to POLINT.

LIBRARY
SLATEC

CATEGORY
E1B

TYPE
DOUBLE PRECISION (POLCOF-S, DPOLCF-D)

KEYWORDS
COEFFICIENTS, POLYNOMIAL

AUTHOR
Huddleston, R. E., (SNLL)

DESCRIPTION
Abstract Subroutine DPOLCF computes the coefficients of the polynomial fit (including Hermite polynomial fits ) produced by a previous call to DPLINT. The coefficients of the polynomial, expanded about XX, are stored in the array D. The expansion is of the form P(Z) = D(1) + D(2)*(Z-XX) +D(3)*((Z-XX)**2) + ... + D(N)*((Z-XX)**(N-1)). Between the call to DPLINT and the call to DPOLCF the variable N and the arrays X and C must not be altered. ***** INPUT PARAMETERS *** All TYPE REAL variables are DOUBLE PRECISION *** XX - The point about which the Taylor expansion is to be made. N - **** * N, X, and C must remain unchanged between the X - * call to DPLINT and the call to DPOLCF. C - **** ***** OUTPUT PARAMETER *** All TYPE REAL variables are DOUBLE PRECISION *** D - The array of coefficients for the Taylor expansion as explained in the abstract ***** STORAGE PARAMETER WORK - This is an array to provide internal working storage. It must be dimensioned by at least 2*N in the calling program. **** Note - There are two methods for evaluating the fit produced by DPLINT. You may call DPOLVL to perform the task, or you may call DPOLCF to obtain the coefficients of the Taylor expansion and then write your own evaluation scheme. Due to the inherent errors in the computations of the Taylor expansion from the Newton coefficients produced by DPLINT, much more accuracy may be expected by calling DPOLVL as opposed to writing your own scheme.

REFERENCES
(NONE)

ROUTINES CALLED
(NONE)

REVISION HISTORY (YYMMDD)
890213 DATE WRITTEN
891006 Cosmetic changes to prologue. (WRB)
891024 Corrected KEYWORD section. (WRB)
891024 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)