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version 1.20, 2020/05/21 21:46:01
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*> \brief \b DLATDF |
*> \brief \b DLATDF uses the LU factorization of the n-by-n matrix computed by sgetc2 and computes a contribution to the reciprocal Dif-estimate. |
* |
* |
* =========== 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 DLATDF + dependencies |
*> Download DLATDF + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlatdf.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlatdf.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlatdf.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlatdf.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlatdf.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlatdf.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DLATDF( IJOB, N, Z, LDZ, RHS, RDSUM, RDSCAL, IPIV, |
* SUBROUTINE DLATDF( IJOB, N, Z, LDZ, RHS, RDSUM, RDSCAL, IPIV, |
* JPIV ) |
* JPIV ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER IJOB, LDZ, N |
* INTEGER IJOB, LDZ, N |
* DOUBLE PRECISION RDSCAL, RDSUM |
* DOUBLE PRECISION RDSCAL, RDSUM |
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* INTEGER IPIV( * ), JPIV( * ) |
* INTEGER IPIV( * ), JPIV( * ) |
* DOUBLE PRECISION RHS( * ), Z( LDZ, * ) |
* DOUBLE PRECISION RHS( * ), Z( LDZ, * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \par Purpose: |
*> \par Purpose: |
* ============= |
* ============= |
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*> Zx = +-e - f with the sign giving the greater value |
*> Zx = +-e - f with the sign giving the greater value |
*> of 2-norm(x). About 5 times as expensive as Default. |
*> of 2-norm(x). About 5 times as expensive as Default. |
*> IJOB .ne. 2: Local look ahead strategy where all entries of |
*> IJOB .ne. 2: Local look ahead strategy where all entries of |
*> the r.h.s. b is choosen as either +1 or -1 (Default). |
*> the r.h.s. b is chosen as either +1 or -1 (Default). |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in] N |
*> \param[in] N |
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*> RHS is DOUBLE PRECISION array, dimension (N) |
*> RHS is DOUBLE PRECISION array, dimension (N) |
*> On entry, RHS contains contributions from other subsystems. |
*> On entry, RHS contains contributions from other subsystems. |
*> On exit, RHS contains the solution of the subsystem with |
*> On exit, RHS contains the solution of the subsystem with |
*> entries acoording to the value of IJOB (see above). |
*> entries according to the value of IJOB (see above). |
*> \endverbatim |
*> \endverbatim |
*> |
*> |
*> \param[in,out] RDSUM |
*> \param[in,out] RDSUM |
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* 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 |
*> \date June 2016 |
* |
* |
*> \ingroup doubleOTHERauxiliary |
*> \ingroup doubleOTHERauxiliary |
* |
* |
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SUBROUTINE DLATDF( IJOB, N, Z, LDZ, RHS, RDSUM, RDSCAL, IPIV, |
SUBROUTINE DLATDF( IJOB, N, Z, LDZ, RHS, RDSUM, RDSCAL, IPIV, |
$ JPIV ) |
$ JPIV ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK auxiliary 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 2011 |
* June 2016 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER IJOB, LDZ, N |
INTEGER IJOB, LDZ, N |
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* |
* |
* Solve for U-part, look-ahead for RHS(N) = +-1. This is not done |
* Solve for U-part, look-ahead for RHS(N) = +-1. This is not done |
* in BSOLVE and will hopefully give us a better estimate because |
* in BSOLVE and will hopefully give us a better estimate because |
* any ill-conditioning of the original matrix is transfered to U |
* any ill-conditioning of the original matrix is transferred to U |
* and not to L. U(N, N) is an approximation to sigma_min(LU). |
* and not to L. U(N, N) is an approximation to sigma_min(LU). |
* |
* |
CALL DCOPY( N-1, RHS, 1, XP, 1 ) |
CALL DCOPY( N-1, RHS, 1, XP, 1 ) |