spdf/afpolin.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.2  1996/10/30 08:27:33  cernlib
   6 * Version 7.04
   7 *
   8 * Revision 1.1.1.1  1996/04/12 15:29:00  plothow
   9 * Version 7.01
  10 *
  11 *
  12 #include "pdf/pilot.h"
  13       SUBROUTINE AFPOLIN(XA,YA,N,X,Y,DY)
  14       PARAMETER (NMAX=10)
  15       DIMENSION XA(NMAX),YA(NMAX),C(NMAX),D(NMAX)
  16       Y=0.
  17       IF(N.GT.NMAX) RETURN
  18       NS=1
  19       DIF=ABS(X-XA(1))
  20       DO 11 I=1,N
  21         DIFT=ABS(X-XA(I))
  22         IF (DIFT.LT.DIF) THEN
  23           NS=I
  24           DIF=DIFT
  25         ENDIF
  26         C(I)=YA(I)
  27         D(I)=YA(I)
  28 11    CONTINUE
  29       Y=YA(NS)
  30       NS=NS-1
  31       DO 13 M=1,N-1
  32         DO 12 I=1,N-M
  33           HO=XA(I)-X
  34           HP=XA(I+M)-X
  35           W=C(I+1)-D(I)
  36           DEN=HO-HP
  37 C         IF(DEN.EQ.0.)PAUSE
  38           DEN=W/DEN
  39           D(I)=HP*DEN
  40           C(I)=HO*DEN
  41 12      CONTINUE
  42         IF (2*NS.LT.N-M)THEN
  43           DY=C(NS+1)
  44         ELSE
  45           DY=D(NS)
  46           NS=NS-1
  47         ENDIF
  48         Y=Y+DY
  49 13    CONTINUE
  50       RETURN
  51       END