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NAME
     dgedi - compute the determinant and  inverse  of  a  general
     matrix A, which has been LU-factored by xGECO or xGEFA.

SYNOPSIS
     SUBROUTINE DGEDI (DA, LDA, N, IPIVOT, DDET, DWORK, JOB)

     SUBROUTINE SGEDI (SA, LDA, N, IPIVOT, SDET, SWORK, JOB)

     SUBROUTINE ZGEDI (ZA, LDA, N, IPIVOT, ZDET, ZWORK, JOB)

     SUBROUTINE CGEDI (CA, LDA, N, IPIVOT, CDET, CWORK, JOB)



     #include <sunperf.h>

     void dgedi(double *da, int lda, int n, int  *ipivot,  double
               *det, int job) ;

     void sgedi(float *sa, int lda, int  n,  int  *ipivot,  float
               *det, int job) ;

     void zgedi(doublecomplex *za, int lda, int n,  int  *ipivot,
               doublecomplex *det, int job) ;

     void cgedi(complex *ca, int lda, int n, int *ipivot, complex
               *det, int job) ;

ARGUMENTS
     xA        On entry, the LU factorization of the matrix A, as
               computed  by xGECO or xGEFA.  On exit, the inverse
               of the  original  matrix  A  if  the  inverse  was
               requested, otherwise it is unchanged.

     LDA       Leading dimension of the array A as specified in a
               dimension or type statement.  LDA >= max(1,N).

     N         Order of the original matrix A.  N >= 0.

     IPIVOT    Pivot vector as computed by xGECO or xGEFA.

     xDET      On exit, the determinant of  the  matrix  A.   The
               determinant  is  stored as b * (10**expon) where b
               is stored in DET(1) and expon is stored in DET(2).
               1.0 >= |DET(1)| >= 10.0  or  DET(1) = 0.0.

     xWORK     Scratch array with a dimension of N.

     JOB       Determines which  operation  the  subroutine  will
               perform:
                    11   both determinant and inverse
                    01   inverse only
                    10   determinant only

SAMPLE PROGRAM
           PROGRAM TEST
           IMPLICIT NONE
     C
           INTEGER           INVDET, LDA, N
           PARAMETER        (INVDET = 11)
           PARAMETER        (N = 4)
           PARAMETER        (LDA = N)
     C
           DOUBLE PRECISION  A(LDA,N), DET(2), RCOND, WORK(N)
           INTEGER           ICOL, IPIVOT(N), IROW, JOB
     C
           EXTERNAL          DGECO, DGEDI
     C
     C     Initialize the array A to store the matrix A shown below.  Its
     C     exact inverse also is shown below.
     C
     C         -3   1                         1    1  1  1  1
     C     A =  1  -2   1        A**(-1) = - --- * 1  3  3  3
     C              1  -2   1                 2    1  3  5  5
     C                  1  -1                      1  3  5  7
     C
           DATA A / -3.0D0, 1.0D0, 2*0.0D0, 1.0D0, -2.0D0, 1.0D0, 2*0.0D0,
          $         1.0D0, -2.0D0, 1.0D0, 2*0.0D0, 1.0D0, -1.0D0 /
     C
           PRINT 1000
           PRINT 1010, ((A(IROW,ICOL), ICOL = 1, N), IROW = 1, N)
           CALL DGECO (A, LDA, N, IPIVOT, RCOND, WORK)
           JOB = INVDET
           CALL DGEDI (A, LDA, N, IPIVOT, DET, WORK, JOB)
           PRINT 1020
           PRINT 1010, ((A(IROW,ICOL), ICOL = 1, N), IROW = 1, N)
           PRINT 1030, DET(1) * (1.0D1 ** DET(2))
     C
      1000 FORMAT (1X, 'A:')
      1010 FORMAT (4(3X, F5.1))
      1020 FORMAT (/1X, 'A**(-1):')
      1030 FORMAT (/1X, 'det(A) =', F6.1)
     C
           END

SAMPLE OUTPUT
      A:
         -3.0     1.0     0.0     0.0
          1.0    -2.0     1.0     0.0
          0.0     1.0    -2.0     1.0
          0.0     0.0     1.0    -1.0

      A**(-1):
         -0.5    -0.5    -0.5    -0.5
         -0.5    -1.5    -1.5    -1.5
         -0.5    -1.5    -2.5    -2.5
         -0.5    -1.5    -2.5    -3.5

      det(A) =   2.0

Партнёры:

Хостинг: