DTRDI(3F)

NAME
     DTRDI   - DTRDI computes the determinant and inverse of a double
     precision triangular matrix.


SYNOPSYS
      SUBROUTINE DTRDI(T,LDT,N,DET,JOB,INFO)

DESCRIPTION
     On Entry

     T DOUBLE PRECISION(LDT,N)
        T contains the triangular matrix.  The zero
        elements of the matrix are not referenced, and
        the corresponding elements of the array can be
        used to store other information.

     LDT INTEGER
        LDT is the leading dimension of the array T.

     N INTEGER
        N is the order of the system.

     JOB INTEGER
        = 010       no det, inverse of lower triangular.
        = 011       no det, inverse of upper triangular.
        = 100       det, no inverse.
        = 110       det, inverse of lower triangular.
        = 111       det, inverse of upper triangular.  On Return

     T inverse of original matrix if requested.
        Otherwise unchanged.

     DET DOUBLE PRECISION(2)
        determinant of original matrix if requested.
        Otherwise not referenced.
        DETERMINANT = DET(1) * 10.0**DET(2)
        with  1.0 .LE. DABS(DET(1)) .LT. 10.0
        or  DET(1) .EQ. 0.0 .

     INFO INTEGER
        INFO contains zero if the system is nonsingular
        and the inverse is requested.
        Otherwise INFO contains the index of
        a zero diagonal element of T.  LINPACK.  This version dated 08/14/78 .
     Cleve Moler, University of New Mexico, Argonne National Lab.  Subroutines
     and Functions BLAS DAXPY,DSCAL Fortran DABS,MOD