POLCOF(3)

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

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

LIBRARY
SLATEC

CATEGORY
E1B

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

KEYWORDS
COEFFICIENTS, POLYNOMIAL

AUTHOR
Huddleston, R. E., (SNLL)

DESCRIPTION
Written by Robert E. Huddleston, Sandia Laboratories, Livermore Abstract Subroutine POLCOF computes the coefficients of the polynomial fit (including Hermite polynomial fits ) produced by a previous call to POLINT. 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 POLINT and the call to POLCOF the variable N and the arrays X and C must not be altered. ***** INPUT PARAMETERS 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 POLINT or the call to POLCOF. C - **** ***** OUTPUT PARAMETER 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 POLINT. You may call POLYVL to perform the task, or you may call POLCOF 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 POLINT, much more accuracy may be expected by calling POLYVL as opposed to writing your own scheme.

REFERENCES
(NONE)

ROUTINES CALLED
(NONE)

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