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

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