CTITLEMTRPL1 -- PARAMETER INTERPLOATION                                 00000100
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR               L. B. LIN                                    00000200
CA    DESIGNER             DENNIS CORRIGAN                              00000300
CA    LANGUAGE             FORTRAN                                      00000400
CA    SYSTEM               IBM AND CRAY                                 00000500
CA    WRITTEN              03-15-83                                     00000600
C     REVISED                                                           00000700
C                                                                       00000800
CA                                                                      00000900
CA                                                                      00001000
CA    CALL MTRPL1 (N, REC, STM, R, S)                                   00001100
CA         INPUT      N = NUMBER OF CONTROL POINTS                  I4  00001200
CA         INPUT    REC = RECORD NUMBERS AT CONTROL POINTS          R4  00001300
CA         INPUT    STM = PARAMETER VALUES AT CONTROL POINTS        R4  00001400
CA         INPUT      R = RECORD NUMBER FOR WHICH THE VALUE IS          00001500
CA                        DESIRED                                   R4  00001600
CA         OUTPUT     S = OUTPUT INTERPOLATED PARAMETER             R4  00001700
CA                                                                      00001800
CA                                                                      00001900
CA    THIS ROUTINE PERFORMS A PARAMETER INTERPOLATION.                  00002000
CAEND                                                                   00002100
C     EJECT                                                             00002200
      SUBROUTINE MTRPL1 (N, REC, STM, R, S)                             00002300
C                                                                       00002400
      DIMENSION REC(1), STM(1)                                          00002500
C                                                                       00002600
      I = 1                                                             00002700
      IF (R .GT. REC(I))  GO TO 20                                      00002800
10    S = STM(I)                                                        00002900
      RETURN                                                            00003000
C                                                                       00003100
20    I = N                                                             00003200
      IF (R .GE. REC(I)) GO TO 10                                       00003300
C                                                                       00003400
C              MUST INTERPOLATE                                         00003500
C                                                                       00003600
      N2C = N - 1                                                       00003700
C                                                                       00003800
      DO 30 I = 1,N2C                                                   00003900
C                                                                       00004000
      IF (R .GT. REC(I+1)) GO TO 30                                     00004100
      GO TO 40                                                          00004200
30    CONTINUE                                                          00004300
C                                                                       00004400
40    D = REC(I+1) - REC(I)                                             00004500
      S = STM(I+1)*(R-REC(I)) + STM(I)*(REC(I+1)-R)                     00004600
      S = S/D                                                           00004700
      RETURN                                                            00004800
      END                                                               00004900