version 1.9, 2011/11/21 22:19:34
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version 1.19, 2023/08/07 08:38:57
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*> \brief \b DLARRK |
*> \brief \b DLARRK computes one eigenvalue of a symmetric tridiagonal matrix T to suitable accuracy. |
* |
* |
* =========== 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 DLARRK + dependencies |
*> Download DLARRK + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarrk.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarrk.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarrk.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarrk.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarrk.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarrk.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DLARRK( N, IW, GL, GU, |
* SUBROUTINE DLARRK( N, IW, GL, GU, |
* D, E2, PIVMIN, RELTOL, W, WERR, INFO) |
* D, E2, PIVMIN, RELTOL, W, WERR, INFO) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER INFO, IW, N |
* INTEGER INFO, IW, N |
* DOUBLE PRECISION PIVMIN, RELTOL, GL, GU, W, WERR |
* DOUBLE PRECISION PIVMIN, RELTOL, GL, GU, W, WERR |
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* .. Array Arguments .. |
* .. Array Arguments .. |
* DOUBLE PRECISION D( * ), E2( * ) |
* DOUBLE PRECISION D( * ), E2( * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \par Purpose: |
*> \par Purpose: |
* ============= |
* ============= |
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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. |
* |
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*> \date November 2011 |
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* |
* |
*> \ingroup auxOTHERauxiliary |
*> \ingroup OTHERauxiliary |
* |
* |
* ===================================================================== |
* ===================================================================== |
SUBROUTINE DLARRK( N, IW, GL, GU, |
SUBROUTINE DLARRK( N, IW, GL, GU, |
$ D, E2, PIVMIN, RELTOL, W, WERR, INFO) |
$ D, E2, PIVMIN, RELTOL, W, WERR, INFO) |
* |
* |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK auxiliary 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 |
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* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INFO, IW, N |
INTEGER INFO, IW, N |
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* .. |
* .. |
* .. Executable Statements .. |
* .. Executable Statements .. |
* |
* |
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* Quick return if possible |
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* |
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IF( N.LE.0 ) THEN |
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INFO = 0 |
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RETURN |
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END IF |
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* |
* Get machine constants |
* Get machine constants |
EPS = DLAMCH( 'P' ) |
EPS = DLAMCH( 'P' ) |
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