# polcof.f

          SUBROUTINE POLCOF (XX, N, X, C, D, WORK)
    C***BEGIN PROLOGUE  POLCOF
    C***PURPOSE  Compute the coefficients of the polynomial fit (including
    C            Hermite polynomial fits) produced by a previous call to
    C            POLINT.
    C***LIBRARY   SLATEC
    C***CATEGORY  E1B
    C***TYPE      SINGLE PRECISION (POLCOF-S, DPOLCF-D)
    C***KEYWORDS  COEFFICIENTS, POLYNOMIAL
    C***AUTHOR  Huddleston, R. E., (SNLL)
    C***DESCRIPTION
    C
    C     Written by Robert E. Huddleston, Sandia Laboratories, Livermore
    C
    C     Abstract
    C        Subroutine POLCOF computes the coefficients of the polynomial
    C     fit (including Hermite polynomial fits ) produced by a previous
    C     call to POLINT. The coefficients of the polynomial, expanded about
    C     XX, are stored in the array D. The expansion is of the form
    C     P(Z) = D(1) + D(2)*(Z-XX) +D(3)*((Z-XX)**2) + ... +
    C                                                  D(N)*((Z-XX)**(N-1)).
    C     Between the call to POLINT and the call to POLCOF the variable N
    C     and the arrays X and C must not be altered.
    C
    C     *****  INPUT PARAMETERS
    C
    C     XX   - The point about which the Taylor expansion is to be made.
    C
    C     N    - ****
    C            *     N, X, and C must remain unchanged between the
    C     X    - *     call to POLINT or the call to POLCOF.
    C     C    - ****
    C
    C     *****  OUTPUT PARAMETER
    C
    C     D    - The array of coefficients for the Taylor expansion as
    C            explained in the abstract
    C
    C     *****  STORAGE PARAMETER
    C
    C     WORK - This is an array to provide internal working storage. It
    C            must be dimensioned by at least 2*N in the calling program.
    C
    C
    C     **** Note - There are two methods for evaluating the fit produced
    C     by POLINT. You may call POLYVL to perform the task, or you may
    C     call POLCOF to obtain the coefficients of the Taylor expansion and
    C     then write your own evaluation scheme. Due to the inherent errors
    C     in the computations of the Taylor expansion from the Newton
    C     coefficients produced by POLINT, much more accuracy may be
    C     expected by calling POLYVL as opposed to writing your own scheme.
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  (NONE)
    C***REVISION HISTORY  (YYMMDD)
    C   890213  DATE WRITTEN
    C   891024  Corrected KEYWORD section.  (WRB)
    C   891024  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C***END PROLOGUE  POLCOF