version 1.12, 2012/12/14 14:22:29
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version 1.22, 2023/08/07 08:38:50
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* |
* |
* =========== 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 DGETC2 + dependencies |
*> Download DGETC2 + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetc2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetc2.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dgetc2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dgetc2.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dgetc2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dgetc2.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DGETC2( N, A, LDA, IPIV, JPIV, INFO ) |
* SUBROUTINE DGETC2( N, A, LDA, IPIV, JPIV, INFO ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER INFO, LDA, N |
* INTEGER INFO, LDA, N |
* .. |
* .. |
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* INTEGER IPIV( * ), JPIV( * ) |
* INTEGER IPIV( * ), JPIV( * ) |
* DOUBLE PRECISION A( LDA, * ) |
* DOUBLE PRECISION A( LDA, * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \par Purpose: |
*> \par Purpose: |
* ============= |
* ============= |
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*> \verbatim |
*> \verbatim |
*> INFO is INTEGER |
*> INFO is INTEGER |
*> = 0: successful exit |
*> = 0: successful exit |
*> > 0: if INFO = k, U(k, k) is likely to produce owerflow if |
*> > 0: if INFO = k, U(k, k) is likely to produce overflow if |
*> we try to solve for x in Ax = b. So U is perturbed to |
*> we try to solve for x in Ax = b. So U is perturbed to |
*> avoid the overflow. |
*> avoid the overflow. |
*> \endverbatim |
*> \endverbatim |
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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 September 2012 |
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* |
* |
*> \ingroup doubleGEauxiliary |
*> \ingroup doubleGEauxiliary |
* |
* |
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* ===================================================================== |
* ===================================================================== |
SUBROUTINE DGETC2( N, A, LDA, IPIV, JPIV, INFO ) |
SUBROUTINE DGETC2( N, A, LDA, IPIV, JPIV, INFO ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.4.2) -- |
* -- 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..-- |
* September 2012 |
|
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INFO, LDA, N |
INTEGER INFO, LDA, N |
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DOUBLE PRECISION BIGNUM, EPS, SMIN, SMLNUM, XMAX |
DOUBLE PRECISION BIGNUM, EPS, SMIN, SMLNUM, XMAX |
* .. |
* .. |
* .. External Subroutines .. |
* .. External Subroutines .. |
EXTERNAL DGER, DSWAP |
EXTERNAL DGER, DSWAP, DLABAD |
* .. |
* .. |
* .. External Functions .. |
* .. External Functions .. |
DOUBLE PRECISION DLAMCH |
DOUBLE PRECISION DLAMCH |
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* .. |
* .. |
* .. Executable Statements .. |
* .. Executable Statements .. |
* |
* |
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INFO = 0 |
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* |
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* Quick return if possible |
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* |
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IF( N.EQ.0 ) |
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$ RETURN |
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* |
* Set constants to control overflow |
* Set constants to control overflow |
* |
* |
INFO = 0 |
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EPS = DLAMCH( 'P' ) |
EPS = DLAMCH( 'P' ) |
SMLNUM = DLAMCH( 'S' ) / EPS |
SMLNUM = DLAMCH( 'S' ) / EPS |
BIGNUM = ONE / SMLNUM |
BIGNUM = ONE / SMLNUM |
CALL DLABAD( SMLNUM, BIGNUM ) |
CALL DLABAD( SMLNUM, BIGNUM ) |
* |
* |
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* Handle the case N=1 by itself |
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* |
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IF( N.EQ.1 ) THEN |
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IPIV( 1 ) = 1 |
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JPIV( 1 ) = 1 |
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IF( ABS( A( 1, 1 ) ).LT.SMLNUM ) THEN |
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INFO = 1 |
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A( 1, 1 ) = SMLNUM |
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END IF |
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RETURN |
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END IF |
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* |
* Factorize A using complete pivoting. |
* Factorize A using complete pivoting. |
* Set pivots less than SMIN to SMIN. |
* Set pivots less than SMIN to SMIN. |
* |
* |
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A( N, N ) = SMIN |
A( N, N ) = SMIN |
END IF |
END IF |
* |
* |
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* Set last pivots to N |
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* |
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IPIV( N ) = N |
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JPIV( N ) = N |
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* |
RETURN |
RETURN |
* |
* |
* End of DGETC2 |
* End of DGETC2 |