5 * Revision 1.1.1.1 1996/04/01 15:02:26 mclareni
10 SUBROUTINE DSPVD1(F,K,M,T,C,NERR)
12 #include "gen/imp64.inc"
16 PARAMETER (NAME = 'DSPVD1')
18 ************************************************************************
19 * NORBAS, VERSION: 15.03.1993
20 ************************************************************************
22 * DSPVD1 COMPUTES THE COEFFICIENTS C(1),...,C(M-K-1) OF A POLYNOMIAL
23 * VARIATION DIMINISHING SPLINE APPROXIMATION S(X) IN B-SPLINE
26 * S(X) = SUMME(I=1,...,M-K-1) C(I) * B(I,K)(X)
28 * TO A USER SUPPLIED FUNCTION Y=F(X).
30 * THE FUNCTIONS B(I,K)(X) ARE NORMALIZED B-SPLINES OF DEGREE K
31 * (0<= K <= 25) WITH INDEX I (1 <= I <= M-K-1) OVER A SET OF
33 * T(1),T(2), ... ,T(M) ( M >= 2*K+2 )
34 * (KNOTS IN ASCENDING ORDER, WITH MULTIPLICITIES NOT GREATER
36 * THE FUNCTION VALUE OF THE NORMALIZED B-SPLINE B(I,K)(X) IS
37 * IDENTICALLY ZERO OUTSIDE THE INTERVAL T(I) <= X < T(I+K+1).
38 * THE NORMALIZATION OF N(X) = B(I,K)(X) IS SUCH THAT THE INTGRAL OF
39 * N(X) OVER THE WHOLE X-RANGE EQUALS
40 * ( T(I+K+1) - T(I) ) / (K+1) .
44 * F (DOUBLE PRECISION) USER SUPPLIED FUNCTION F(X) FOR WHICH
45 * THE CORRESPONDING SPLINE APPROXIMATION HAS TO BE COMPUTED.
46 * K (INTEGER) DEGREE (= ORDER - 1) OF B-SPLINES.
47 * M (INTEGER) NUMBER OF KNOTS FOR THE B-SPLINES.
48 * T (DOUBLE PRECISION) ARRAY OF AT LEAST ORDER M CONTAINING THE
50 * C (DOUBLE PRECISION) ARRAY OF AT LEAST ORDER M-K-1. ON EXIT
51 * C(1),...,C(M-K-1) CONTAIN THE COEFFICIENTS OF THE B-SPLINE
52 * REPRESENTATION OF S(X).
53 * NERR (INTEGER) ERROR INDICATOR. ON EXIT:
54 * = 0: NO ERROR DETECTED
55 * = 1: AT LEAST ONE OF THE CONSTANTS K , M IS ILLEGAL
59 * IF ONE OF THE FOLLOWING RELATION IS SATISFIED BY THE CHOSEN INPUT-
60 * PARAMETERS THE PROGRAM RETURNS, AND AN ERROR MESSAGE IS PRINTED:
64 ************************************************************************
69 IF(K .LT. 1 .OR. K .GT. 25) THEN
70 WRITE(ERRTXT,101) 'K',K
71 CALL MTLPRT(NAME,'E210.1',ERRTXT)
72 ELSEIF(M .LT. 2*K+2) THEN
73 WRITE(ERRTXT,101) 'M',M
74 CALL MTLPRT(NAME,'E210.2',ERRTXT)
79 10 C(I)=F(R*DVSUM(K,T(I+1),T(I+2)))
84 101 FORMAT(1X,A5,' =',I6,' NOT IN RANGE')