--- rpl/lapack/lapack/zgbsv.f 2010/12/21 13:53:42 1.7 +++ rpl/lapack/lapack/zgbsv.f 2011/11/21 20:43:08 1.8 @@ -1,9 +1,171 @@ +*> \brief ZGBSV computes the solution to system of linear equations A * X = B for GB matrices (simple driver) +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download ZGBSV + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE ZGBSV( N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO ) +* +* .. Scalar Arguments .. +* INTEGER INFO, KL, KU, LDAB, LDB, N, NRHS +* .. +* .. Array Arguments .. +* INTEGER IPIV( * ) +* COMPLEX*16 AB( LDAB, * ), B( LDB, * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> ZGBSV computes the solution to a complex system of linear equations +*> A * X = B, where A is a band matrix of order N with KL subdiagonals +*> and KU superdiagonals, and X and B are N-by-NRHS matrices. +*> +*> The LU decomposition with partial pivoting and row interchanges is +*> used to factor A as A = L * U, where L is a product of permutation +*> and unit lower triangular matrices with KL subdiagonals, and U is +*> upper triangular with KL+KU superdiagonals. The factored form of A +*> is then used to solve the system of equations A * X = B. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The number of linear equations, i.e., 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 matrix B. NRHS >= 0. +*> \endverbatim +*> +*> \param[in,out] AB +*> \verbatim +*> AB is COMPLEX*16 array, dimension (LDAB,N) +*> On entry, the matrix A in band storage, in rows KL+1 to +*> 2*KL+KU+1; rows 1 to KL of the array need not be set. +*> The j-th column of A is stored in the j-th column of the +*> array AB as follows: +*> AB(KL+KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+KL) +*> On exit, details of the factorization: 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. +*> See below for further details. +*> \endverbatim +*> +*> \param[in] LDAB +*> \verbatim +*> LDAB is INTEGER +*> The leading dimension of the array AB. LDAB >= 2*KL+KU+1. +*> \endverbatim +*> +*> \param[out] IPIV +*> \verbatim +*> IPIV is INTEGER array, dimension (N) +*> The pivot indices that define the permutation matrix P; +*> row i of the matrix was interchanged with row IPIV(i). +*> \endverbatim +*> +*> \param[in,out] B +*> \verbatim +*> B is COMPLEX*16 array, dimension (LDB,NRHS) +*> On entry, the N-by-NRHS right hand side matrix B. +*> On exit, if INFO = 0, the N-by-NRHS solution matrix X. +*> \endverbatim +*> +*> \param[in] LDB +*> \verbatim +*> LDB is INTEGER +*> The leading dimension of the array B. LDB >= max(1,N). +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit +*> < 0: if INFO = -i, the i-th argument had an illegal value +*> > 0: if INFO = i, U(i,i) is exactly zero. The factorization +*> has been completed, but the factor U is exactly +*> singular, and the solution has not been computed. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2011 +* +*> \ingroup complex16GBsolve +* +*> \par Further Details: +* ===================== +*> +*> \verbatim +*> +*> The band storage scheme is illustrated by the following example, when +*> M = N = 6, KL = 2, KU = 1: +*> +*> On entry: On exit: +*> +*> * * * + + + * * * u14 u25 u36 +*> * * + + + + * * u13 u24 u35 u46 +*> * a12 a23 a34 a45 a56 * u12 u23 u34 u45 u56 +*> a11 a22 a33 a44 a55 a66 u11 u22 u33 u44 u55 u66 +*> a21 a32 a43 a54 a65 * m21 m32 m43 m54 m65 * +*> a31 a42 a53 a64 * * m31 m42 m53 m64 * * +*> +*> Array elements marked * are not used by the routine; elements marked +*> + need not be set on entry, but are required by the routine to store +*> elements of U because of fill-in resulting from the row interchanges. +*> \endverbatim +*> +* ===================================================================== SUBROUTINE ZGBSV( N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO ) * -* -- LAPACK driver routine (version 3.2) -- +* -- LAPACK driver 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 +* November 2011 * * .. Scalar Arguments .. INTEGER INFO, KL, KU, LDAB, LDB, N, NRHS @@ -13,88 +175,6 @@ COMPLEX*16 AB( LDAB, * ), B( LDB, * ) * .. * -* Purpose -* ======= -* -* ZGBSV computes the solution to a complex system of linear equations -* A * X = B, where A is a band matrix of order N with KL subdiagonals -* and KU superdiagonals, and X and B are N-by-NRHS matrices. -* -* The LU decomposition with partial pivoting and row interchanges is -* used to factor A as A = L * U, where L is a product of permutation -* and unit lower triangular matrices with KL subdiagonals, and U is -* upper triangular with KL+KU superdiagonals. The factored form of A -* is then used to solve the system of equations A * X = B. -* -* Arguments -* ========= -* -* N (input) INTEGER -* The number of linear equations, i.e., 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 matrix B. NRHS >= 0. -* -* AB (input/output) COMPLEX*16 array, dimension (LDAB,N) -* On entry, the matrix A in band storage, in rows KL+1 to -* 2*KL+KU+1; rows 1 to KL of the array need not be set. -* The j-th column of A is stored in the j-th column of the -* array AB as follows: -* AB(KL+KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+KL) -* On exit, details of the factorization: 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. -* See below for further details. -* -* LDAB (input) INTEGER -* The leading dimension of the array AB. LDAB >= 2*KL+KU+1. -* -* IPIV (output) INTEGER array, dimension (N) -* The pivot indices that define the permutation matrix P; -* row i of the matrix was interchanged with row IPIV(i). -* -* B (input/output) COMPLEX*16 array, dimension (LDB,NRHS) -* On entry, the N-by-NRHS right hand side matrix B. -* On exit, if INFO = 0, the N-by-NRHS solution matrix X. -* -* LDB (input) INTEGER -* The leading dimension of the array B. LDB >= max(1,N). -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value -* > 0: if INFO = i, U(i,i) is exactly zero. The factorization -* has been completed, but the factor U is exactly -* singular, and the solution has not been computed. -* -* Further Details -* =============== -* -* The band storage scheme is illustrated by the following example, when -* M = N = 6, KL = 2, KU = 1: -* -* On entry: On exit: -* -* * * * + + + * * * u14 u25 u36 -* * * + + + + * * u13 u24 u35 u46 -* * a12 a23 a34 a45 a56 * u12 u23 u34 u45 u56 -* a11 a22 a33 a44 a55 a66 u11 u22 u33 u44 u55 u66 -* a21 a32 a43 a54 a65 * m21 m32 m43 m54 m65 * -* a31 a42 a53 a64 * * m31 m42 m53 m64 * * -* -* Array elements marked * are not used by the routine; elements marked -* + need not be set on entry, but are required by the routine to store -* elements of U because of fill-in resulting from the row interchanges. -* * ===================================================================== * * .. External Subroutines ..