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Diffstat (limited to 'SRC/ztrcon.f')
| -rw-r--r-- | SRC/ztrcon.f | 190 |
1 files changed, 130 insertions, 60 deletions
diff --git a/SRC/ztrcon.f b/SRC/ztrcon.f index 6dc12f7a..55cfa51e 100644 --- a/SRC/ztrcon.f +++ b/SRC/ztrcon.f @@ -1,12 +1,138 @@ +*> \brief \b ZTRCON +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +* Definition +* ========== +* +* SUBROUTINE ZTRCON( NORM, UPLO, DIAG, N, A, LDA, RCOND, WORK, +* RWORK, INFO ) +* +* .. Scalar Arguments .. +* CHARACTER DIAG, NORM, UPLO +* INTEGER INFO, LDA, N +* DOUBLE PRECISION RCOND +* .. +* .. Array Arguments .. +* DOUBLE PRECISION RWORK( * ) +* COMPLEX*16 A( LDA, * ), WORK( * ) +* .. +* +* Purpose +* ======= +* +*>\details \b Purpose: +*>\verbatim +*> +*> ZTRCON estimates the reciprocal of the condition number of a +*> triangular matrix A, in either the 1-norm or the infinity-norm. +*> +*> The norm of A is computed and an estimate is obtained for +*> norm(inv(A)), then the reciprocal of the condition number is +*> computed as +*> RCOND = 1 / ( norm(A) * norm(inv(A)) ). +*> +*>\endverbatim +* +* Arguments +* ========= +* +*> \param[in] NORM +*> \verbatim +*> NORM is CHARACTER*1 +*> Specifies whether the 1-norm condition number or the +*> infinity-norm condition number is required: +*> = '1' or 'O': 1-norm; +*> = 'I': Infinity-norm. +*> \endverbatim +*> +*> \param[in] UPLO +*> \verbatim +*> UPLO is CHARACTER*1 +*> = 'U': A is upper triangular; +*> = 'L': A is lower triangular. +*> \endverbatim +*> +*> \param[in] DIAG +*> \verbatim +*> DIAG is CHARACTER*1 +*> = 'N': A is non-unit triangular; +*> = 'U': A is unit triangular. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in] A +*> \verbatim +*> A is COMPLEX*16 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. +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> LDA is INTEGER +*> The leading dimension of the array A. LDA >= max(1,N). +*> \endverbatim +*> +*> \param[out] RCOND +*> \verbatim +*> RCOND is DOUBLE PRECISION +*> The reciprocal of the condition number of the matrix A, +*> computed as RCOND = 1/(norm(A) * norm(inv(A))). +*> \endverbatim +*> +*> \param[out] WORK +*> \verbatim +*> WORK is COMPLEX*16 array, dimension (2*N) +*> \endverbatim +*> +*> \param[out] RWORK +*> \verbatim +*> RWORK is DOUBLE PRECISION array, dimension (N) +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit +*> < 0: if INFO = -i, the i-th argument had an illegal value +*> \endverbatim +*> +* +* Authors +* ======= +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2011 +* +*> \ingroup complex16OTHERcomputational +* +* ===================================================================== SUBROUTINE ZTRCON( NORM, UPLO, DIAG, N, A, LDA, RCOND, WORK, $ RWORK, INFO ) * -* -- LAPACK routine (version 3.2) -- +* -- LAPACK computational routine (version 3.2) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* November 2006 -* -* Modified to call ZLACN2 in place of ZLACON, 10 Feb 03, SJH. +* November 2011 * * .. Scalar Arguments .. CHARACTER DIAG, NORM, UPLO @@ -18,62 +144,6 @@ COMPLEX*16 A( LDA, * ), WORK( * ) * .. * -* Purpose -* ======= -* -* ZTRCON estimates the reciprocal of the condition number of a -* triangular matrix A, in either the 1-norm or the infinity-norm. -* -* The norm of A is computed and an estimate is obtained for -* norm(inv(A)), then the reciprocal of the condition number is -* computed as -* RCOND = 1 / ( norm(A) * norm(inv(A)) ). -* -* Arguments -* ========= -* -* NORM (input) CHARACTER*1 -* Specifies whether the 1-norm condition number or the -* infinity-norm condition number is required: -* = '1' or 'O': 1-norm; -* = 'I': Infinity-norm. -* -* UPLO (input) CHARACTER*1 -* = 'U': A is upper triangular; -* = 'L': A is lower triangular. -* -* DIAG (input) CHARACTER*1 -* = 'N': A is non-unit triangular; -* = 'U': A is unit triangular. -* -* N (input) INTEGER -* The order of the matrix A. N >= 0. -* -* A (input) COMPLEX*16 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 (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,N). -* -* RCOND (output) DOUBLE PRECISION -* The reciprocal of the condition number of the matrix A, -* computed as RCOND = 1/(norm(A) * norm(inv(A))). -* -* WORK (workspace) COMPLEX*16 array, dimension (2*N) -* -* RWORK (workspace) DOUBLE PRECISION array, dimension (N) -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value -* * ===================================================================== * * .. Parameters .. |