TESTING/LIN/dtrt01.f(3)    Library Functions Manual    TESTING/LIN/dtrt01.f(3)

NAME
       TESTING/LIN/dtrt01.f

SYNOPSIS
   Functions/Subroutines
       subroutine dtrt01 (uplo, diag, n, a, lda, ainv, ldainv, rcond, work,
           resid)
           DTRT01

Function/Subroutine Documentation
   subroutine dtrt01 (character uplo, character diag, integer n, double
       precision, dimension( lda, * ) a, integer lda, double precision,
       dimension( ldainv, * ) ainv, integer ldainv, double precision rcond,
       double precision, dimension( * ) work, double precision resid)
       DTRT01

       Purpose:


            DTRT01 computes the residual for a triangular matrix A times its
            inverse:
               RESID = norm( A*AINV - I ) / ( N * norm(A) * norm(AINV) * EPS ),
            where EPS is the machine epsilon.

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                     Specifies whether the matrix A is upper or lower triangular.
                     = 'U':  Upper triangular
                     = 'L':  Lower triangular

           DIAG

                     DIAG is CHARACTER*1
                     Specifies whether or not the matrix A is unit triangular.
                     = 'N':  Non-unit triangular
                     = 'U':  Unit triangular

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     The triangular matrix A.  If UPLO = 'U', the leading n by n
                     upper triangular part of the array A contains the upper
                     triangular matrix, and the strictly lower triangular part of
                     A is not referenced.  If UPLO = 'L', the leading n by n lower
                     triangular part of the array A contains the lower triangular
                     matrix, and the strictly upper triangular part of A is not
                     referenced.  If DIAG = 'U', the diagonal elements of A are
                     also not referenced and are assumed to be 1.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,N).

           AINV

                     AINV is DOUBLE PRECISION array, dimension (LDAINV,N)
                     On entry, the (triangular) inverse of the matrix A, in the
                     same storage format as A.
                     On exit, the contents of AINV are destroyed.

           LDAINV

                     LDAINV is INTEGER
                     The leading dimension of the array AINV.  LDAINV >= max(1,N).

           RCOND

                     RCOND is DOUBLE PRECISION
                     The reciprocal condition number of A, computed as
                     1/(norm(A) * norm(AINV)).

           WORK

                     WORK is DOUBLE PRECISION array, dimension (N)

           RESID

                     RESID is DOUBLE PRECISION
                     norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS )

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 122 of file dtrt01.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/LIN/dtrt01.f(3)