*
* $Id$
*
* $Log$
* Revision 1.1.1.2  1996/10/30 08:27:34  cernlib
* Version 7.04
*
* Revision 1.1.1.1  1996/04/12 15:29:02  plothow
* Version 7.01
*
*
#include "pdf/pilot.h"
C
      FUNCTION AUGETFV(X,FVL)
C  LOGARITHMIC INTERPOLATOR - WATCH OUT FOR NEGATIVE
C  FUNCTIONS AND/OR X VALUES OUTSIDE THE RANGE 0 TO 1.
C  NOTE: DIMENSION OF FVL IS OVERWRITTEN BY VALUE USED
C  IN MAIN ROUTINE.
      DIMENSION FVL(25),XGRID(25)
      DATA NX,XGRID/25,.001,.002,.004,.008,.016,.032,.064,.1,.15,
     *.2,.25,.3,.35,.4,.45,.5,.55,.6,.65,.7,.75,.8,.85,.9,.95/
      AUGETFV=0.
      DO 1 I=1,NX
      IF(X.LT.XGRID(I)) GO TO 2
    1 CONTINUE
    2 I=I-1
      IF(I.EQ.0) THEN
         I=I+1
      ELSE IF(I.GT.23) THEN
         I=23
      ENDIF
      J=I+1
      K=J+1
      AXI= LOG(XGRID(I))
      BXI= LOG(1.-XGRID(I))
      AXJ= LOG(XGRID(J))
      BXJ= LOG(1.-XGRID(J))
      AXK= LOG(XGRID(K))
      BXK= LOG(1.-XGRID(K))
      FI= LOG(ABS(FVL(I)) +1.E-15)
      FJ= LOG(ABS(FVL(J)) +1.E-16)
      FK= LOG(ABS(FVL(K)) +1.E-17)
      DET=AXI*(BXJ-BXK)+AXJ*(BXK-BXI)+AXK*(BXI-BXJ)
      ALOGA=(FI*(AXJ*BXK-AXK*BXJ)+FJ*(AXK*BXI-AXI*BXK)+FK*(AXI*BXJ-AXJ*
     $ BXI))/DET
      ALPHA=(FI*(BXJ-BXK)+FJ*(BXK-BXI)+FK*(BXI-BXJ))/DET
      BETA=(FI*(AXK-AXJ)+FJ*(AXI-AXK)+FK*(AXJ-AXI))/DET
      IF(ABS(ALPHA).GT.99..OR.ABS(BETA).GT.99..OR.ABS(ALOGA).GT.99.)
     1RETURN
C      IF(ALPHA.GT.50..OR.BETA.GT.50.) THEN
C         WRITE(6,2001) X,FVL
C 2001    FORMAT(8E12.4)
C         WRITE(6,2001) ALPHA,BETA,ALOGA,DET
C      ENDIF
      AUGETFV=EXP(ALOGA)*X**ALPHA*(1.-X)**BETA
      RETURN
      END