version 1.17, 2017/06/17 10:53:50
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version 1.22, 2023/08/07 08:38:51
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*> DGSVJ1 is called from DGESVJ as a pre-processor and that is its main |
*> DGSVJ1 is called from DGESVJ as a pre-processor and that is its main |
*> purpose. It applies Jacobi rotations in the same way as DGESVJ does, but |
*> purpose. It applies Jacobi rotations in the same way as DGESVJ does, but |
*> it targets only particular pivots and it does not check convergence |
*> it targets only particular pivots and it does not check convergence |
*> (stopping criterion). Few tunning parameters (marked by [TP]) are |
*> (stopping criterion). Few tuning parameters (marked by [TP]) are |
*> available for the implementer. |
*> available for the implementer. |
*> |
*> |
*> Further Details |
*> Further Details |
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*> In terms of the columns of A, the first N1 columns are rotated 'against' |
*> In terms of the columns of A, the first N1 columns are rotated 'against' |
*> the remaining N-N1 columns, trying to increase the angle between the |
*> the remaining N-N1 columns, trying to increase the angle between the |
*> corresponding subspaces. The off-diagonal block is N1-by(N-N1) and it is |
*> corresponding subspaces. The off-diagonal block is N1-by(N-N1) and it is |
*> tiled using quadratic tiles of side KBL. Here, KBL is a tunning parmeter. |
*> tiled using quadratic tiles of side KBL. Here, KBL is a tuning parameter. |
*> The number of sweeps is given in NSWEEP and the orthogonality threshold |
*> The number of sweeps is given in NSWEEP and the orthogonality threshold |
*> is given in TOL. |
*> is given in TOL. |
*> \endverbatim |
*> \endverbatim |
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*> \param[in] MV |
*> \param[in] MV |
*> \verbatim |
*> \verbatim |
*> MV is INTEGER |
*> MV is INTEGER |
*> If JOBV .EQ. 'A', then MV rows of V are post-multipled by a |
*> If JOBV = 'A', then MV rows of V are post-multipled by a |
*> sequence of Jacobi rotations. |
*> sequence of Jacobi rotations. |
*> If JOBV = 'N', then MV is not referenced. |
*> If JOBV = 'N', then MV is not referenced. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in,out] V |
*> \param[in,out] V |
*> \verbatim |
*> \verbatim |
*> V is DOUBLE PRECISION array, dimension (LDV,N) |
*> V is DOUBLE PRECISION array, dimension (LDV,N) |
*> If JOBV .EQ. 'V' then N rows of V are post-multipled by a |
*> If JOBV = 'V', then N rows of V are post-multipled by a |
*> sequence of Jacobi rotations. |
*> sequence of Jacobi rotations. |
*> If JOBV .EQ. 'A' then MV rows of V are post-multipled by a |
*> If JOBV = 'A', then MV rows of V are post-multipled by a |
*> sequence of Jacobi rotations. |
*> sequence of Jacobi rotations. |
*> If JOBV = 'N', then V is not referenced. |
*> If JOBV = 'N', then V is not referenced. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] LDV |
*> \param[in] LDV |
*> \verbatim |
*> \verbatim |
*> LDV is INTEGER |
*> LDV is INTEGER |
*> The leading dimension of the array V, LDV >= 1. |
*> The leading dimension of the array V, LDV >= 1. |
*> If JOBV = 'V', LDV .GE. N. |
*> If JOBV = 'V', LDV >= N. |
*> If JOBV = 'A', LDV .GE. MV. |
*> If JOBV = 'A', LDV >= MV. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] EPS |
*> \param[in] EPS |
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*> TOL is DOUBLE PRECISION |
*> TOL is DOUBLE PRECISION |
*> TOL is the threshold for Jacobi rotations. For a pair |
*> TOL is the threshold for Jacobi rotations. For a pair |
*> A(:,p), A(:,q) of pivot columns, the Jacobi rotation is |
*> A(:,p), A(:,q) of pivot columns, the Jacobi rotation is |
*> applied only if DABS(COS(angle(A(:,p),A(:,q)))) .GT. TOL. |
*> applied only if DABS(COS(angle(A(:,p),A(:,q)))) > TOL. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] NSWEEP |
*> \param[in] NSWEEP |
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*> \param[in] LWORK |
*> \param[in] LWORK |
*> \verbatim |
*> \verbatim |
*> LWORK is INTEGER |
*> LWORK is INTEGER |
*> LWORK is the dimension of WORK. LWORK .GE. M. |
*> LWORK is the dimension of WORK. LWORK >= M. |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[out] INFO |
*> \param[out] INFO |
*> \verbatim |
*> \verbatim |
*> INFO is INTEGER |
*> INFO is INTEGER |
*> = 0 : successful exit. |
*> = 0: successful exit. |
*> < 0 : if INFO = -i, then the i-th argument had an illegal value |
*> < 0: if INFO = -i, then the i-th argument had an illegal value |
*> \endverbatim |
*> \endverbatim |
* |
* |
* Authors: |
* Authors: |
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*> \author Univ. of Colorado Denver |
*> \author Univ. of Colorado Denver |
*> \author NAG Ltd. |
*> \author NAG Ltd. |
* |
* |
*> \date June 2016 |
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* |
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*> \ingroup doubleOTHERcomputational |
*> \ingroup doubleOTHERcomputational |
* |
* |
*> \par Contributors: |
*> \par Contributors: |
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SUBROUTINE DGSVJ1( JOBV, M, N, N1, A, LDA, D, SVA, MV, V, LDV, |
SUBROUTINE DGSVJ1( JOBV, M, N, N1, A, LDA, D, SVA, MV, V, LDV, |
$ EPS, SFMIN, TOL, NSWEEP, WORK, LWORK, INFO ) |
$ EPS, SFMIN, TOL, NSWEEP, WORK, LWORK, INFO ) |
* |
* |
* -- LAPACK computational routine (version 3.7.0) -- |
* -- 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..-- |
* June 2016 |
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* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
DOUBLE PRECISION EPS, SFMIN, TOL |
DOUBLE PRECISION EPS, SFMIN, TOL |
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EXTERNAL IDAMAX, LSAME, DDOT, DNRM2 |
EXTERNAL IDAMAX, LSAME, DDOT, DNRM2 |
* .. |
* .. |
* .. External Subroutines .. |
* .. External Subroutines .. |
EXTERNAL DAXPY, DCOPY, DLASCL, DLASSQ, DROTM, DSWAP |
EXTERNAL DAXPY, DCOPY, DLASCL, DLASSQ, DROTM, DSWAP, |
|
$ XERBLA |
* .. |
* .. |
* .. Executable Statements .. |
* .. Executable Statements .. |
* |
* |