CTITLEMTRPLT -- PARAMETER INTERPLOATION (FOR TWO PARAMETER VALUES)      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 MTRPLT (N, REC, STM, ETM, R, S, E)                           00001100
CA         INPUT      N = NUMBER OF CONTROL POINTS                  I4  00001200
CA         INPUT    REC = RECORD NUMBERS AT CONTROL POINTS          R4  00001300
CA         INPUT    STM = 1ST PARAMETER VALUES AT CONTROL POINTS    R4  00001400
CA         INPUT    ETM = 2ND PARAMETER VALUES AT CONTROL POINTS    R4  00001500
CA         INPUT      R = RECORD NUMBER FOR WHICH THE VALUE IS          00001600
CA                        DESIRED                                   R4  00001700
CA         OUTPUT     S = OUTPUT INTERPOLATED 1ST PARAMETER         R4  00001800
CA         OUTPUT     E = OUTPUT INTERPOLATED 2ND PARAMETER         R4  00001900
CA                                                                      00002000
CA                                                                      00002100
CA    THIS ROUTINE PERFORMS A TWO-VALUE PARAMETER INTERPOLATION.        00002200
CAEND                                                                   00002300
C     EJECT                                                             00002400
      SUBROUTINE MTRPLT (N, REC, STM, ETM, R, S, E)                     00002500
C                                                                       00002600
      DIMENSION REC(1), STM(1), ETM(1)                                  00002700
C                                                                       00002800
      I = 1                                                             00002900
      IF (R .GT. REC(I))  GO TO 20                                      00003000
10    S = STM(I)                                                        00003100
      E = ETM(I)                                                        00003200
      RETURN                                                            00003300
C                                                                       00003400
20    I = N                                                             00003500
      IF (R .GE. REC(I)) GO TO 10                                       00003600
C                                                                       00003700
C              MUST INTERPOLATE                                         00003800
C                                                                       00003900
      N2C = N - 1                                                       00004000
C                                                                       00004100
      DO 30 I = 1, N2C                                                  00004200
C                                                                       00004300
      IF (R .GT. REC(I+1)) GO TO 30                                     00004400
      GO TO 40                                                          00004500
30    CONTINUE                                                          00004600
C                                                                       00004700
40    D = REC(I+1) - REC(I)                                             00004800
      S = STM(I+1)*(R-REC(I)) + STM(I)*(REC(I+1)-R)                     00004900
      E = ETM(I+1)*(R-REC(I)) + ETM(I)*(REC(I+1)-R)                     00005000
      S = S/D                                                           00005100
      E = E/D                                                           00005200
      RETURN                                                            00005300
      END                                                               00005400