dtrt06.f3

!>
!> DTRT06 computes a test ratio comparing RCOND (the reciprocal
!> condition number of a triangular matrix A) and RCONDC, the estimate
!> computed by DTRCON.  Information about the triangular matrix A is
!> used if one estimate is zero and the other is non-zero to decide if
!> underflow in the estimate is justified.
!> 

RCOND

!>          RCOND is DOUBLE PRECISION
!>          The estimate of the reciprocal condition number obtained by
!>          forming the explicit inverse of the matrix A and computing
!>          RCOND = 1/( norm(A) * norm(inv(A)) ).
!> 

RCONDC

!>          RCONDC is DOUBLE PRECISION
!>          The estimate of the reciprocal condition number computed by
!>          DTRCON.
!> 

UPLO

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

DIAG

!>          DIAG is CHARACTER
!>          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).
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (N)
!> 

RAT

!>          RAT is DOUBLE PRECISION
!>          The test ratio.  If both RCOND and RCONDC are nonzero,
!>             RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.
!>          If RAT = 0, the two estimates are exactly the same.
!> 

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.