version 1.7, 2012/12/14 14:22:41
|
version 1.15, 2023/08/07 08:39:11
|
Line 2
|
Line 2
|
* |
* |
* =========== DOCUMENTATION =========== |
* =========== DOCUMENTATION =========== |
* |
* |
* Online html documentation available at |
* Online html documentation available at |
* http://www.netlib.org/lapack/explore-html/ |
* http://www.netlib.org/lapack/explore-html/ |
* |
* |
*> \htmlonly |
*> \htmlonly |
*> Download DSYTRS2 + dependencies |
*> Download DSYTRS2 + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dsytrs2.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DSYTRS2( UPLO, N, NRHS, A, LDA, IPIV, B, LDB, |
* SUBROUTINE DSYTRS2( UPLO, N, NRHS, A, LDA, IPIV, B, LDB, |
* WORK, INFO ) |
* WORK, INFO ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* CHARACTER UPLO |
* CHARACTER UPLO |
* INTEGER INFO, LDA, LDB, N, NRHS |
* INTEGER INFO, LDA, LDB, N, NRHS |
Line 29
|
Line 29
|
* INTEGER IPIV( * ) |
* INTEGER IPIV( * ) |
* DOUBLE PRECISION A( LDA, * ), B( LDB, * ), WORK( * ) |
* DOUBLE PRECISION A( LDA, * ), B( LDB, * ), WORK( * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \par Purpose: |
*> \par Purpose: |
* ============= |
* ============= |
Line 66
|
Line 66
|
*> of the matrix B. NRHS >= 0. |
*> of the matrix B. NRHS >= 0. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] A |
*> \param[in,out] A |
*> \verbatim |
*> \verbatim |
*> A is DOUBLE PRECISION array, dimension (LDA,N) |
*> A is DOUBLE PRECISION array, dimension (LDA,N) |
*> The block diagonal matrix D and the multipliers used to |
*> The block diagonal matrix D and the multipliers used to |
*> obtain the factor U or L as computed by DSYTRF. |
*> obtain the factor U or L as computed by DSYTRF. |
|
*> Note that A is input / output. This might be counter-intuitive, |
|
*> and one may think that A is input only. A is input / output. This |
|
*> is because, at the start of the subroutine, we permute A in a |
|
*> "better" form and then we permute A back to its original form at |
|
*> the end. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] LDA |
*> \param[in] LDA |
Line 101
|
Line 106
|
*> |
*> |
*> \param[out] WORK |
*> \param[out] WORK |
*> \verbatim |
*> \verbatim |
*> WORK is REAL array, dimension (N) |
*> WORK is DOUBLE PRECISION array, dimension (N) |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[out] INFO |
*> \param[out] INFO |
Line 114
|
Line 119
|
* Authors: |
* Authors: |
* ======== |
* ======== |
* |
* |
*> \author Univ. of Tennessee |
*> \author Univ. of Tennessee |
*> \author Univ. of California Berkeley |
*> \author Univ. of California Berkeley |
*> \author Univ. of Colorado Denver |
*> \author Univ. of Colorado Denver |
*> \author NAG Ltd. |
*> \author NAG Ltd. |
* |
|
*> \date November 2011 |
|
* |
* |
*> \ingroup doubleSYcomputational |
*> \ingroup doubleSYcomputational |
* |
* |
* ===================================================================== |
* ===================================================================== |
SUBROUTINE DSYTRS2( UPLO, N, NRHS, A, LDA, IPIV, B, LDB, |
SUBROUTINE DSYTRS2( UPLO, N, NRHS, A, LDA, IPIV, B, LDB, |
$ WORK, INFO ) |
$ WORK, INFO ) |
* |
* |
* -- LAPACK computational routine (version 3.4.0) -- |
* -- LAPACK computational routine -- |
* -- 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 2011 |
|
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
CHARACTER UPLO |
CHARACTER UPLO |
Line 195
|
Line 197
|
* |
* |
* Solve A*X = B, where A = U*D*U**T. |
* Solve A*X = B, where A = U*D*U**T. |
* |
* |
* P**T * B |
* P**T * B |
K=N |
K=N |
DO WHILE ( K .GE. 1 ) |
DO WHILE ( K .GE. 1 ) |
IF( IPIV( K ).GT.0 ) THEN |
IF( IPIV( K ).GT.0 ) THEN |
Line 220
|
Line 222
|
CALL DTRSM('L','U','N','U',N,NRHS,ONE,A,LDA,B,LDB) |
CALL DTRSM('L','U','N','U',N,NRHS,ONE,A,LDA,B,LDB) |
* |
* |
* Compute D \ B -> B [ D \ (U \P**T * B) ] |
* Compute D \ B -> B [ D \ (U \P**T * B) ] |
* |
* |
I=N |
I=N |
DO WHILE ( I .GE. 1 ) |
DO WHILE ( I .GE. 1 ) |
IF( IPIV(I) .GT. 0 ) THEN |
IF( IPIV(I) .GT. 0 ) THEN |
Line 272
|
Line 274
|
* |
* |
* Solve A*X = B, where A = L*D*L**T. |
* Solve A*X = B, where A = L*D*L**T. |
* |
* |
* P**T * B |
* P**T * B |
K=1 |
K=1 |
DO WHILE ( K .LE. N ) |
DO WHILE ( K .LE. N ) |
IF( IPIV( K ).GT.0 ) THEN |
IF( IPIV( K ).GT.0 ) THEN |
Line 297
|
Line 299
|
CALL DTRSM('L','L','N','U',N,NRHS,ONE,A,LDA,B,LDB) |
CALL DTRSM('L','L','N','U',N,NRHS,ONE,A,LDA,B,LDB) |
* |
* |
* Compute D \ B -> B [ D \ (L \P**T * B) ] |
* Compute D \ B -> B [ D \ (L \P**T * B) ] |
* |
* |
I=1 |
I=1 |
DO WHILE ( I .LE. N ) |
DO WHILE ( I .LE. N ) |
IF( IPIV(I) .GT. 0 ) THEN |
IF( IPIV(I) .GT. 0 ) THEN |
Line 319
|
Line 321
|
END DO |
END DO |
* |
* |
* Compute (L**T \ B) -> B [ L**T \ (D \ (L \P**T * B) ) ] |
* Compute (L**T \ B) -> B [ L**T \ (D \ (L \P**T * B) ) ] |
* |
* |
CALL DTRSM('L','L','T','U',N,NRHS,ONE,A,LDA,B,LDB) |
CALL DTRSM('L','L','T','U',N,NRHS,ONE,A,LDA,B,LDB) |
* |
* |
* P * B [ P * (L**T \ (D \ (L \P**T * B) )) ] |
* P * B [ P * (L**T \ (D \ (L \P**T * B) )) ] |