SUBROUTINE PDA_DPOLCF (XX, N, X, C, D, WORK)
***BEGIN PROLOGUE PDA_DPOLCF
***PURPOSE 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, PDA_DPOLCF-D)
***KEYWORDS COEFFICIENTS, POLYNOMIAL
***AUTHOR Huddleston, R. E., (SNLL)
***DESCRIPTION
Abstract
Subroutine PDA_DPOLCF computes the coefficients of the polynomial
fit (including Hermite polynomial fits ) produced by a previous
call to PDA_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 PDA_DPLINT and the call to PDA_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 PDA_DPLINT and the call to PDA_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 PDA_DPLINT. You may call PDA_DPOLVL to perform the task, or you may
call PDA_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 PDA_DPLINT, much more accuracy may be
expected by calling PDA_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)
***END PROLOGUE PDA_DPOLCF