CTITLEMPLYFT -- POLYNOMIAL INTERPOLATION                                00000010
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA                                                                      00000020
CA    AUTHOR                      DAVE  D. THOMPSON                     00000030
CA    DESIGNER                    DAVE  D. THOMPSON                     00000040
CA    LANGUAGE                    FORTRAN IV                            00000050
C     WRITTEN                     1971                                  00000060
CA                                                                      00000070
CA                                                                      00000080
CA    PURPOSE: THIS SUBROUTINE PERFORMS POLYNOMIAL INTERPOLATION        00000090
CA             FOR UNIFORMLY SAMPLED DATA PARAMETERS.                   00000100
CA                                                                      00000110
CA                                                                      00000120
CA                                                                      00000130
CA    CALL MPLYFT  (Y,XX,YY,ID)                                         00000140
CA                                                                      00000150
CA          INPUT     Y = DATA ARRAY (LENGTH ID+1)                   R4 00000160
CA          INPUT    XX = SAMPLE NUMBER (NONINTEGER) OF DESIRED      R4 00000170
CA                        DATA VALUE (INPUT)                            00000180
CA          INPUT    ID = DEGREE OF POLYNOMIAL INTERPOLATION        I4  00000190
CA          OUTPUT   YY = INTERPOLATED DATA VALUE AT SAMPLE XX      R4  00000200
CA                                                                      00000210
      SUBROUTINE MPLYFT(Y,XX,YY,ID)                                     00000220
      DIMENSION Y(1)                                                    00000230
      N=ID+1                                                            00000240
      YY=0.                                                             00000250
          DO                                                        20  00000260
     *    I = 1, N                                                      00000270
          P = Y(I)                                                      00000280
              DO                                                    10  00000290
     *        J = 1, N                                                  00000300
              IF(J .EQ. I) GO TO                                    10  00000310
              P = P * (XX - J) / (I - J)                                00000320
C                                                                       00000330
   10         CONTINUE                                                  00000340
C                                                                       00000350
   20     YY = YY + P                                                   00000360
      RETURN                                                            00000370
      END                                                               00000380