CTITLESALMPAP -- POLY. INTERPOLATOR FOR NON-UNIFORM DATA
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CABS  SALMPAP - POLYNOMIAL INTERPOLATOR FOR NON-UNIFORM DATA
C
CSUBROUTINE SALMPAP
C
C     SUBROUTINE SALMPAP(X,Y,XX,YY,ID)
C
C     COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991.
C
C     ALL RIGHTS RESERVED.  NO PART OF THIS PROGRAM MAY BE PHOTOCOPIED,
C     REPRODUCED, OR  TRANSLATED TO ANOTHER PROGRAM LANGUAGE WITHOUT THE
C     PRIOR CONSENT OF ATLANTIC RICHFIELD COMPANY.
C
CA    AUTHOR                      DAVE THOMPSON
CA    DESIGNER                    DAVE THOMPSON
CA    LANGUAGE                    FORTRAN H
CA    SYSTEM                      S/370
C     WRITTEN                     UNKNOWN
CA
CA    PURPOSE OF PROGRAM:
CA
CA    THIS SUBROUTINE PERFORMS POLYNOMIAL INTERPOLATION FOR NON-
CA    UNIFORMLY SAMPLED DATA.
CA
CA    CALLING SEQUENCE:
CA
CA    CALL SALMPAP (X,Y,XX,YY,ID)
CA
CA    IN         X   R4    INDEPENDENT SAMPLE ARRAY OF LENGTH ID+1 (ALL
CA                         VALUES MUST BE UNIQUE)
CA    IN         Y   R4    CORRESPONDING DEPENDENT SAMPLE ARRAY OF
CA                         LENGTH    ID + 1
CA    IN        XX   R4    VALUE OF INDEPENDENT VARIABLE FOR WHICH
CA                         DEPENDENT VALUE IS DESIRED
CA   OUT        YY   R4    INTERPOLATED VALUE OF DEPENDENT VARIABLE AT
CA                         XX
CA    IN        ID   I4    DEGREE OF POLYNOMIAL INTERPOLATION
CA
CA
CA
CA    SUBROUTINES CALLED:       NONE
CA    EJECT
CAEND
C***********************************************************************
C
C
      SUBROUTINE SALMPAP(X,Y,XX,YY,ID)
      IMPLICIT INTEGER (A-Z)
C
      REAL X, XX, Y, YY, P
      DIMENSION X(*),Y(*)
C
      N = ID + 1
      YY = 0.
C
      DO 120 I = 1, N
         P = Y(I)
C
         DO 100 J = 1, N
            IF (J .NE. I) P = P * (XX - X(J) )  / (X(I) - X(J) )
 100     CONTINUE
C
         YY = YY + P
 120  CONTINUE
C
      RETURN
      END