SLATEC Routines --- BSPDR ---

*DECK BSPDR
      SUBROUTINE BSPDR (T, A, N, K, NDERIV, AD)
C***BEGIN PROLOGUE  BSPDR
C***PURPOSE  Use the B-representation to construct a divided difference
C            table preparatory to a (right) derivative calculation.
C***LIBRARY   SLATEC
C***CATEGORY  E3
C***TYPE      SINGLE PRECISION (BSPDR-S, DBSPDR-D)
C***KEYWORDS  B-SPLINE, DATA FITTING, DIFFERENTIATION OF SPLINES,
C             INTERPOLATION
C***AUTHOR  Amos, D. E., (SNLA)
C***DESCRIPTION
C
C     Written by Carl de Boor and modified by D. E. Amos
C
C     Abstract
C         BSPDR is the BSPLDR routine of the reference.
C
C         BSPDR uses the B-representation (T,A,N,K) to construct a
C         divided difference table ADIF preparatory to a (right)
C         derivative calculation in BSPEV.  The lower triangular matrix
C         ADIF is stored in vector AD by columns.  The arrays are
C         related by
C
C           ADIF(I,J) = AD(I-J+1 + (2*N-J+2)*(J-1)/2)
C
C         I = J,N , J = 1,NDERIV .
C
C     Description of Arguments
C         Input
C          T       - knot vector of length N+K
C          A       - B-spline coefficient vector of length N
C          N       - number of B-spline coefficients
C                    N = sum of knot multiplicities-K
C          K       - order of the spline, K .GE. 1
C          NDERIV  - number of derivatives, 1 .LE. NDERIV .LE. K.
C                    NDERIV=1 gives the zero-th derivative = function
C                    value
C
C         Output
C          AD      - table of differences in a vector of length
C                    (2*N-NDERIV+1)*NDERIV/2 for input to BSPEV
C
C     Error Conditions
C         Improper input is a fatal error
C
C***REFERENCES  Carl de Boor, Package for calculating with B-splines,
C                 SIAM Journal on Numerical Analysis 14, 3 (June 1977),
C                 pp. 441-472.
C***ROUTINES CALLED  XERMSG
C***REVISION HISTORY  (YYMMDD)
C   800901  DATE WRITTEN
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
C   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C   920501  Reformatted the REFERENCES section.  (WRB)
C***END PROLOGUE  BSPDR