version 1.5, 2010/08/07 13:22:15
|
version 1.18, 2018/05/29 07:17:54
|
Line 1
|
Line 1
|
|
*> \brief <b> DGTSV computes the solution to system of linear equations A * X = B for GT matrices </b> |
|
* |
|
* =========== DOCUMENTATION =========== |
|
* |
|
* Online html documentation available at |
|
* http://www.netlib.org/lapack/explore-html/ |
|
* |
|
*> \htmlonly |
|
*> Download DGTSV + dependencies |
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgtsv.f"> |
|
*> [TGZ]</a> |
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dgtsv.f"> |
|
*> [ZIP]</a> |
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dgtsv.f"> |
|
*> [TXT]</a> |
|
*> \endhtmlonly |
|
* |
|
* Definition: |
|
* =========== |
|
* |
|
* SUBROUTINE DGTSV( N, NRHS, DL, D, DU, B, LDB, INFO ) |
|
* |
|
* .. Scalar Arguments .. |
|
* INTEGER INFO, LDB, N, NRHS |
|
* .. |
|
* .. Array Arguments .. |
|
* DOUBLE PRECISION B( LDB, * ), D( * ), DL( * ), DU( * ) |
|
* .. |
|
* |
|
* |
|
*> \par Purpose: |
|
* ============= |
|
*> |
|
*> \verbatim |
|
*> |
|
*> DGTSV solves the equation |
|
*> |
|
*> A*X = B, |
|
*> |
|
*> where A is an n by n tridiagonal matrix, by Gaussian elimination with |
|
*> partial pivoting. |
|
*> |
|
*> Note that the equation A**T*X = B may be solved by interchanging the |
|
*> order of the arguments DU and DL. |
|
*> \endverbatim |
|
* |
|
* Arguments: |
|
* ========== |
|
* |
|
*> \param[in] N |
|
*> \verbatim |
|
*> N is INTEGER |
|
*> The order of the matrix A. N >= 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] DL |
|
*> \verbatim |
|
*> DL is DOUBLE PRECISION array, dimension (N-1) |
|
*> On entry, DL must contain the (n-1) sub-diagonal elements of |
|
*> A. |
|
*> |
|
*> On exit, DL is overwritten by the (n-2) elements of the |
|
*> second super-diagonal of the upper triangular matrix U from |
|
*> the LU factorization of A, in DL(1), ..., DL(n-2). |
|
*> \endverbatim |
|
*> |
|
*> \param[in,out] D |
|
*> \verbatim |
|
*> D is DOUBLE PRECISION array, dimension (N) |
|
*> On entry, D must contain the diagonal elements of A. |
|
*> |
|
*> On exit, D is overwritten by the n diagonal elements of U. |
|
*> \endverbatim |
|
*> |
|
*> \param[in,out] DU |
|
*> \verbatim |
|
*> DU is DOUBLE PRECISION array, dimension (N-1) |
|
*> On entry, DU must contain the (n-1) super-diagonal elements |
|
*> of A. |
|
*> |
|
*> On exit, DU is overwritten by the (n-1) elements of the first |
|
*> super-diagonal of U. |
|
*> \endverbatim |
|
*> |
|
*> \param[in,out] B |
|
*> \verbatim |
|
*> B is DOUBLE PRECISION array, dimension (LDB,NRHS) |
|
*> On entry, the N by NRHS matrix of 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, and the solution |
|
*> has not been computed. The factorization has not been |
|
*> completed unless i = N. |
|
*> \endverbatim |
|
* |
|
* Authors: |
|
* ======== |
|
* |
|
*> \author Univ. of Tennessee |
|
*> \author Univ. of California Berkeley |
|
*> \author Univ. of Colorado Denver |
|
*> \author NAG Ltd. |
|
* |
|
*> \date December 2016 |
|
* |
|
*> \ingroup doubleGTsolve |
|
* |
|
* ===================================================================== |
SUBROUTINE DGTSV( N, NRHS, DL, D, DU, B, LDB, INFO ) |
SUBROUTINE DGTSV( N, NRHS, DL, D, DU, B, LDB, INFO ) |
* |
* |
* -- LAPACK routine (version 3.2) -- |
* -- LAPACK driver routine (version 3.7.0) -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* November 2006 |
* December 2016 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INFO, LDB, N, NRHS |
INTEGER INFO, LDB, N, NRHS |
Line 12
|
Line 139
|
DOUBLE PRECISION B( LDB, * ), D( * ), DL( * ), DU( * ) |
DOUBLE PRECISION B( LDB, * ), D( * ), DL( * ), DU( * ) |
* .. |
* .. |
* |
* |
* Purpose |
|
* ======= |
|
* |
|
* DGTSV solves the equation |
|
* |
|
* A*X = B, |
|
* |
|
* where A is an n by n tridiagonal matrix, by Gaussian elimination with |
|
* partial pivoting. |
|
* |
|
* Note that the equation A'*X = B may be solved by interchanging the |
|
* order of the arguments DU and DL. |
|
* |
|
* Arguments |
|
* ========= |
|
* |
|
* N (input) INTEGER |
|
* The order of the matrix A. N >= 0. |
|
* |
|
* NRHS (input) INTEGER |
|
* The number of right hand sides, i.e., the number of columns |
|
* of the matrix B. NRHS >= 0. |
|
* |
|
* DL (input/output) DOUBLE PRECISION array, dimension (N-1) |
|
* On entry, DL must contain the (n-1) sub-diagonal elements of |
|
* A. |
|
* |
|
* On exit, DL is overwritten by the (n-2) elements of the |
|
* second super-diagonal of the upper triangular matrix U from |
|
* the LU factorization of A, in DL(1), ..., DL(n-2). |
|
* |
|
* D (input/output) DOUBLE PRECISION array, dimension (N) |
|
* On entry, D must contain the diagonal elements of A. |
|
* |
|
* On exit, D is overwritten by the n diagonal elements of U. |
|
* |
|
* DU (input/output) DOUBLE PRECISION array, dimension (N-1) |
|
* On entry, DU must contain the (n-1) super-diagonal elements |
|
* of A. |
|
* |
|
* On exit, DU is overwritten by the (n-1) elements of the first |
|
* super-diagonal of U. |
|
* |
|
* B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS) |
|
* On entry, the N by NRHS matrix of 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, and the solution |
|
* has not been computed. The factorization has not been |
|
* completed unless i = N. |
|
* |
|
* ===================================================================== |
* ===================================================================== |
* |
* |
* .. Parameters .. |
* .. Parameters .. |