--- rpl/lapack/lapack/zgbrfs.f 2010/12/21 13:53:42 1.7 +++ rpl/lapack/lapack/zgbrfs.f 2011/11/21 20:43:08 1.8 @@ -1,13 +1,215 @@ +*> \brief \b ZGBRFS +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download ZGBRFS + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE ZGBRFS( TRANS, N, KL, KU, NRHS, AB, LDAB, AFB, LDAFB, +* IPIV, B, LDB, X, LDX, FERR, BERR, WORK, RWORK, +* INFO ) +* +* .. Scalar Arguments .. +* CHARACTER TRANS +* INTEGER INFO, KL, KU, LDAB, LDAFB, LDB, LDX, N, NRHS +* .. +* .. Array Arguments .. +* INTEGER IPIV( * ) +* DOUBLE PRECISION BERR( * ), FERR( * ), RWORK( * ) +* COMPLEX*16 AB( LDAB, * ), AFB( LDAFB, * ), B( LDB, * ), +* $ WORK( * ), X( LDX, * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> ZGBRFS improves the computed solution to a system of linear +*> equations when the coefficient matrix is banded, and provides +*> error bounds and backward error estimates for the solution. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] TRANS +*> \verbatim +*> TRANS is CHARACTER*1 +*> Specifies the form of the system of equations: +*> = 'N': A * X = B (No transpose) +*> = 'T': A**T * X = B (Transpose) +*> = 'C': A**H * X = B (Conjugate transpose) +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in] KL +*> \verbatim +*> KL is INTEGER +*> The number of subdiagonals within the band of A. KL >= 0. +*> \endverbatim +*> +*> \param[in] KU +*> \verbatim +*> KU is INTEGER +*> The number of superdiagonals within the band of A. KU >= 0. +*> \endverbatim +*> +*> \param[in] NRHS +*> \verbatim +*> NRHS is INTEGER +*> The number of right hand sides, i.e., the number of columns +*> of the matrices B and X. NRHS >= 0. +*> \endverbatim +*> +*> \param[in] AB +*> \verbatim +*> AB is COMPLEX*16 array, dimension (LDAB,N) +*> The original band matrix A, stored in rows 1 to KL+KU+1. +*> The j-th column of A is stored in the j-th column of the +*> array AB as follows: +*> AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(n,j+kl). +*> \endverbatim +*> +*> \param[in] LDAB +*> \verbatim +*> LDAB is INTEGER +*> The leading dimension of the array AB. LDAB >= KL+KU+1. +*> \endverbatim +*> +*> \param[in] AFB +*> \verbatim +*> AFB is COMPLEX*16 array, dimension (LDAFB,N) +*> Details of the LU factorization of the band matrix A, as +*> computed by ZGBTRF. U is stored as an upper triangular band +*> matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and +*> the multipliers used during the factorization are stored in +*> rows KL+KU+2 to 2*KL+KU+1. +*> \endverbatim +*> +*> \param[in] LDAFB +*> \verbatim +*> LDAFB is INTEGER +*> The leading dimension of the array AFB. LDAFB >= 2*KL*KU+1. +*> \endverbatim +*> +*> \param[in] IPIV +*> \verbatim +*> IPIV is INTEGER array, dimension (N) +*> The pivot indices from ZGBTRF; for 1<=i<=N, row i of the +*> matrix was interchanged with row IPIV(i). +*> \endverbatim +*> +*> \param[in] B +*> \verbatim +*> B is COMPLEX*16 array, dimension (LDB,NRHS) +*> The right hand side matrix B. +*> \endverbatim +*> +*> \param[in] LDB +*> \verbatim +*> LDB is INTEGER +*> The leading dimension of the array B. LDB >= max(1,N). +*> \endverbatim +*> +*> \param[in,out] X +*> \verbatim +*> X is COMPLEX*16 array, dimension (LDX,NRHS) +*> On entry, the solution matrix X, as computed by ZGBTRS. +*> On exit, the improved solution matrix X. +*> \endverbatim +*> +*> \param[in] LDX +*> \verbatim +*> LDX is INTEGER +*> The leading dimension of the array X. LDX >= max(1,N). +*> \endverbatim +*> +*> \param[out] FERR +*> \verbatim +*> FERR is DOUBLE PRECISION array, dimension (NRHS) +*> The estimated forward error bound for each solution vector +*> X(j) (the j-th column of the solution matrix X). +*> If XTRUE is the true solution corresponding to X(j), FERR(j) +*> is an estimated upper bound for the magnitude of the largest +*> element in (X(j) - XTRUE) divided by the magnitude of the +*> largest element in X(j). The estimate is as reliable as +*> the estimate for RCOND, and is almost always a slight +*> overestimate of the true error. +*> \endverbatim +*> +*> \param[out] BERR +*> \verbatim +*> BERR is DOUBLE PRECISION array, dimension (NRHS) +*> The componentwise relative backward error of each solution +*> vector X(j) (i.e., the smallest relative change in +*> any element of A or B that makes X(j) an exact solution). +*> \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 +* +*> \par Internal Parameters: +* ========================= +*> +*> \verbatim +*> ITMAX is the maximum number of steps of iterative refinement. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2011 +* +*> \ingroup complex16GBcomputational +* +* ===================================================================== SUBROUTINE ZGBRFS( TRANS, N, KL, KU, NRHS, AB, LDAB, AFB, LDAFB, $ IPIV, B, LDB, X, LDX, FERR, BERR, WORK, RWORK, $ INFO ) * -* -- LAPACK routine (version 3.2) -- +* -- LAPACK computational routine (version 3.4.0) -- * -- 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 TRANS @@ -20,99 +222,6 @@ $ WORK( * ), X( LDX, * ) * .. * -* Purpose -* ======= -* -* ZGBRFS improves the computed solution to a system of linear -* equations when the coefficient matrix is banded, and provides -* error bounds and backward error estimates for the solution. -* -* Arguments -* ========= -* -* TRANS (input) CHARACTER*1 -* Specifies the form of the system of equations: -* = 'N': A * X = B (No transpose) -* = 'T': A**T * X = B (Transpose) -* = 'C': A**H * X = B (Conjugate transpose) -* -* N (input) INTEGER -* The order of the matrix A. N >= 0. -* -* KL (input) INTEGER -* The number of subdiagonals within the band of A. KL >= 0. -* -* KU (input) INTEGER -* The number of superdiagonals within the band of A. KU >= 0. -* -* NRHS (input) INTEGER -* The number of right hand sides, i.e., the number of columns -* of the matrices B and X. NRHS >= 0. -* -* AB (input) COMPLEX*16 array, dimension (LDAB,N) -* The original band matrix A, stored in rows 1 to KL+KU+1. -* The j-th column of A is stored in the j-th column of the -* array AB as follows: -* AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(n,j+kl). -* -* LDAB (input) INTEGER -* The leading dimension of the array AB. LDAB >= KL+KU+1. -* -* AFB (input) COMPLEX*16 array, dimension (LDAFB,N) -* Details of the LU factorization of the band matrix A, as -* computed by ZGBTRF. U is stored as an upper triangular band -* matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and -* the multipliers used during the factorization are stored in -* rows KL+KU+2 to 2*KL+KU+1. -* -* LDAFB (input) INTEGER -* The leading dimension of the array AFB. LDAFB >= 2*KL*KU+1. -* -* IPIV (input) INTEGER array, dimension (N) -* The pivot indices from ZGBTRF; for 1<=i<=N, row i of the -* matrix was interchanged with row IPIV(i). -* -* B (input) COMPLEX*16 array, dimension (LDB,NRHS) -* The right hand side matrix B. -* -* LDB (input) INTEGER -* The leading dimension of the array B. LDB >= max(1,N). -* -* X (input/output) COMPLEX*16 array, dimension (LDX,NRHS) -* On entry, the solution matrix X, as computed by ZGBTRS. -* On exit, the improved solution matrix X. -* -* LDX (input) INTEGER -* The leading dimension of the array X. LDX >= max(1,N). -* -* FERR (output) DOUBLE PRECISION array, dimension (NRHS) -* The estimated forward error bound for each solution vector -* X(j) (the j-th column of the solution matrix X). -* If XTRUE is the true solution corresponding to X(j), FERR(j) -* is an estimated upper bound for the magnitude of the largest -* element in (X(j) - XTRUE) divided by the magnitude of the -* largest element in X(j). The estimate is as reliable as -* the estimate for RCOND, and is almost always a slight -* overestimate of the true error. -* -* BERR (output) DOUBLE PRECISION array, dimension (NRHS) -* The componentwise relative backward error of each solution -* vector X(j) (i.e., the smallest relative change in -* any element of A or B that makes X(j) an exact solution). -* -* 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 -* -* Internal Parameters -* =================== -* -* ITMAX is the maximum number of steps of iterative refinement. -* * ===================================================================== * * .. Parameters ..