CTITLEMDETRM -- DETERMINANT EVALUATION                                  00000020
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR               UNKNOWN                                      00000030
CA    DESIGNER             UNKNOWN - PASS ROUTINE CONVERTED BY          00000040
CA                                   GALEN WHIPPLE   08-01-77           00000050
CA    LANGUAGE             FORTRAN                                      00000060
CA    SYSTEM               IBM AND CRAY                                 00000060
CA    WRITTEN              MO-DA-YR                                     00000070
C     REVISED              MO-DA-YR BY PROGRAMMER FOR REASON.           00000080
C     REVISED                                                           00000090
CA                                                                      00000100
CA                                                                      00000110
CA    CALL MDETRM (A, N, D)                                             00000120
CA         INPUT   A = MATRIX                                       R8  00000130
CA         INPUT   N = MATRIX ORDER                                 I4  00000140
CA         OUTPUT  D = DETERMINANT OF THE MATRIX                    R4  00000150
CA                                                                      00000160
CA                                                                      00000170
CA    THIS SUBROUTINE COMPUTES THE DETERMINANT OF THE INPUT MATRIX      00000200
CA    BY TRIANGULATING THE MATRIX AND TAKING THE PRODUCT OF THE         00000210
CA    DIAGONAL ELEMENTS.                                                00000220
CAEND                                                                   00000230
      SUBROUTINE MDETRM(A,N,D)                                          00000240
      DOUBLE PRECISION A,DPRIM,S                                        00000250
      DIMENSION A(N,N)                                                  00000260
      L = N-1                                                           00000270
      DO 10 I=1,L                                                       00000280
      DO 10 J=I,L                                                       00000290
      IF(A(I,I) .EQ. 0.) GO TO 15                                       00000300
      S = -A(J+1,I)/A(I,I)                                              00000310
      IF (S .EQ. 0.) GO TO 10                                           00000320
      DO 5 K=1,N                                                        00000330
    5 A(J+1,K) = S*A(I,K)+A(J+1,K)                                      00000340
   10 CONTINUE                                                          00000350
   15 DPRIM = 1.                                                        00000360
      DO 20 K=1,N                                                       00000370
   20 DPRIM = DPRIM*A(K,K)                                              00000380
      D = SNGL(DPRIM)                                                   00000390
      RETURN                                                            00000400
      END                                                               00000410