version 1.1, 2010/12/21 13:50:36
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version 1.10, 2016/08/27 15:34:30
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SUBROUTINE DLARTGP( F, G, CS, SN, R ) |
*> \brief \b DLARTGP generates a plane rotation so that the diagonal is nonnegative. |
* |
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* Originally DLARTG |
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* -- LAPACK auxiliary routine (version 3.2) -- |
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* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
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* November 2006 |
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* |
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* Adapted to DLARTGP |
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* July 2010 |
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* |
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* .. Scalar Arguments .. |
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DOUBLE PRECISION CS, F, G, R, SN |
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* .. |
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* |
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* Purpose |
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* ======= |
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* |
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* DLARTGP generates a plane rotation so that |
* =========== DOCUMENTATION =========== |
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* [ CS SN ] . [ F ] = [ R ] where CS**2 + SN**2 = 1. |
* Online html documentation available at |
* [ -SN CS ] [ G ] [ 0 ] |
* http://www.netlib.org/lapack/explore-html/ |
* |
* |
* This is a slower, more accurate version of the Level 1 BLAS routine DROTG, |
*> \htmlonly |
* with the following other differences: |
*> Download DLARTGP + dependencies |
* F and G are unchanged on return. |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlartgp.f"> |
* If G=0, then CS=(+/-)1 and SN=0. |
*> [TGZ]</a> |
* If F=0 and (G .ne. 0), then CS=0 and SN=(+/-)1. |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlartgp.f"> |
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*> [ZIP]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlartgp.f"> |
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*> [TXT]</a> |
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*> \endhtmlonly |
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* |
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* Definition: |
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* =========== |
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* |
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* SUBROUTINE DLARTGP( F, G, CS, SN, R ) |
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* |
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* .. Scalar Arguments .. |
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* DOUBLE PRECISION CS, F, G, R, SN |
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* .. |
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* |
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* |
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*> \par Purpose: |
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* ============= |
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*> |
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*> \verbatim |
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*> |
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*> DLARTGP generates a plane rotation so that |
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*> |
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*> [ CS SN ] . [ F ] = [ R ] where CS**2 + SN**2 = 1. |
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*> [ -SN CS ] [ G ] [ 0 ] |
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*> |
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*> This is a slower, more accurate version of the Level 1 BLAS routine DROTG, |
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*> with the following other differences: |
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*> F and G are unchanged on return. |
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*> If G=0, then CS=(+/-)1 and SN=0. |
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*> If F=0 and (G .ne. 0), then CS=0 and SN=(+/-)1. |
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*> |
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*> The sign is chosen so that R >= 0. |
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*> \endverbatim |
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* |
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* Arguments: |
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* ========== |
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* |
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*> \param[in] F |
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*> \verbatim |
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*> F is DOUBLE PRECISION |
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*> The first component of vector to be rotated. |
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*> \endverbatim |
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*> |
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*> \param[in] G |
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*> \verbatim |
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*> G is DOUBLE PRECISION |
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*> The second component of vector to be rotated. |
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*> \endverbatim |
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*> |
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*> \param[out] CS |
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*> \verbatim |
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*> CS is DOUBLE PRECISION |
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*> The cosine of the rotation. |
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*> \endverbatim |
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*> |
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*> \param[out] SN |
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*> \verbatim |
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*> SN is DOUBLE PRECISION |
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*> The sine of the rotation. |
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*> \endverbatim |
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*> |
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*> \param[out] R |
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*> \verbatim |
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*> R is DOUBLE PRECISION |
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*> The nonzero component of the rotated vector. |
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*> |
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*> This version has a few statements commented out for thread safety |
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*> (machine parameters are computed on each entry). 10 feb 03, SJH. |
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*> \endverbatim |
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* |
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* Authors: |
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* ======== |
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* |
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*> \author Univ. of Tennessee |
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*> \author Univ. of California Berkeley |
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*> \author Univ. of Colorado Denver |
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*> \author NAG Ltd. |
* |
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* The sign is chosen so that R >= 0. |
*> \date September 2012 |
* |
* |
* Arguments |
*> \ingroup auxOTHERauxiliary |
* ========= |
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* |
* |
* F (input) DOUBLE PRECISION |
* ===================================================================== |
* The first component of vector to be rotated. |
SUBROUTINE DLARTGP( F, G, CS, SN, R ) |
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* G (input) DOUBLE PRECISION |
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* The second component of vector to be rotated. |
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* |
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* CS (output) DOUBLE PRECISION |
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* The cosine of the rotation. |
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* |
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* SN (output) DOUBLE PRECISION |
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* The sine of the rotation. |
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* R (output) DOUBLE PRECISION |
* -- LAPACK auxiliary routine (version 3.4.2) -- |
* The nonzero component of the rotated vector. |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
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* September 2012 |
* |
* |
* This version has a few statements commented out for thread safety |
* .. Scalar Arguments .. |
* (machine parameters are computed on each entry). 10 feb 03, SJH. |
DOUBLE PRECISION CS, F, G, R, SN |
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* .. |
* |
* |
* ===================================================================== |
* ===================================================================== |
* |
* |