NAME

SYNOPSIS

  SUBROUTINE DTRDI( A, LDA, N, DET, JOB, INFO)
  INTEGER LDA, N, JOB, INFO
  DOUBLE PRECISION A(LDA,*), DET(*)
 
  SUBROUTINE DTRDI_64( A, LDA, N, DET, JOB, INFO)
  INTEGER*8 LDA, N, JOB, INFO
  DOUBLE PRECISION A(LDA,*), DET(*)
 

C INTERFACE

void dtrdi(double *a, int lda, int n, double *det, int job, int *info);

void dtrdi_64(double *a, long lda, long n, double *det, long job, long *info);

ARGUMENTS

* A (input/output)

On entry, the matrix A. On exit, the inverse of the original matrix A if the inverse was requested, otherwise unchanged.

* LDA (input)

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

* N (input)

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

* DET (output)

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.

* JOB (input)

Determines which operation the subroutine will perform:

• 010 no determinant, inverse of lower triangular A

• 011 no determinant, inverse of upper triangular A

• 100 determinant, no inverse

• 110 determinant, inverse of lower triangular A

• 111 determinant, inverse of upper triangular A

* INFO (output)

On exit:

INFO = 0 Subroutine completed normally.

INFO > 0 Contains the index of a zero element of A if the inverse is requested and A is singular.