version 1.10, 2011/11/21 22:19:53
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version 1.19, 2018/05/29 07:18:28
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*> \brief \b ZLARFG |
*> \brief \b ZLARFG generates an elementary reflector (Householder matrix). |
* |
* |
* =========== 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 ZLARFG + dependencies |
*> Download ZLARFG + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarfg.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarfg.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarfg.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarfg.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarfg.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarfg.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU ) |
* SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER INCX, N |
* INTEGER INCX, N |
* COMPLEX*16 ALPHA, TAU |
* COMPLEX*16 ALPHA, TAU |
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* .. Array Arguments .. |
* .. Array Arguments .. |
* COMPLEX*16 X( * ) |
* COMPLEX*16 X( * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \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. |
* |
* |
*> \date November 2011 |
*> \date November 2017 |
* |
* |
*> \ingroup complex16OTHERauxiliary |
*> \ingroup complex16OTHERauxiliary |
* |
* |
* ===================================================================== |
* ===================================================================== |
SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU ) |
SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK auxiliary routine (version 3.8.0) -- |
* -- 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 |
* November 2017 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INCX, N |
INTEGER INCX, N |
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BETA = BETA*RSAFMN |
BETA = BETA*RSAFMN |
ALPHI = ALPHI*RSAFMN |
ALPHI = ALPHI*RSAFMN |
ALPHR = ALPHR*RSAFMN |
ALPHR = ALPHR*RSAFMN |
IF( ABS( BETA ).LT.SAFMIN ) |
IF( (ABS( BETA ).LT.SAFMIN) .AND. (KNT .LT. 20) ) |
$ GO TO 10 |
$ GO TO 10 |
* |
* |
* New BETA is at most 1, at least SAFMIN |
* New BETA is at most 1, at least SAFMIN |