dtrt06.f - Man Page
TESTING/LIN/dtrt06.f
Synopsis
Functions/Subroutines
subroutine dtrt06 (rcond, rcondc, uplo, diag, n, a, lda, work, rat)
DTRT06
Function/Subroutine Documentation
subroutine dtrt06 (double precision rcond, double precision rcondc, character uplo, character diag, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) work, double precision rat)
DTRT06
Purpose:
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.
- Parameters
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.
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 119 of file dtrt06.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page dtrt06(3) is an alias of dtrt06.f(3).
Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK