version 1.12, 2012/12/14 14:22:29
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version 1.18, 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 DGETF2 + dependencies |
*> Download DGETF2 + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetf2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetf2.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dgetf2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dgetf2.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dgetf2.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dgetf2.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO ) |
* SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER INFO, LDA, M, N |
* INTEGER INFO, LDA, M, N |
* .. |
* .. |
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* INTEGER IPIV( * ) |
* INTEGER IPIV( * ) |
* DOUBLE PRECISION A( LDA, * ) |
* DOUBLE PRECISION A( LDA, * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \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 September 2012 |
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* |
* |
*> \ingroup doubleGEcomputational |
*> \ingroup doubleGEcomputational |
* |
* |
* ===================================================================== |
* ===================================================================== |
SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO ) |
SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO ) |
* |
* |
* -- LAPACK computational routine (version 3.4.2) -- |
* -- LAPACK computational 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, M, N |
INTEGER INFO, LDA, M, N |
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PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 ) |
PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 ) |
* .. |
* .. |
* .. Local Scalars .. |
* .. Local Scalars .. |
DOUBLE PRECISION SFMIN |
DOUBLE PRECISION SFMIN |
INTEGER I, J, JP |
INTEGER I, J, JP |
* .. |
* .. |
* .. External Functions .. |
* .. External Functions .. |
DOUBLE PRECISION DLAMCH |
DOUBLE PRECISION DLAMCH |
INTEGER IDAMAX |
INTEGER IDAMAX |
EXTERNAL DLAMCH, IDAMAX |
EXTERNAL DLAMCH, IDAMAX |
* .. |
* .. |
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IF( M.EQ.0 .OR. N.EQ.0 ) |
IF( M.EQ.0 .OR. N.EQ.0 ) |
$ RETURN |
$ RETURN |
* |
* |
* Compute machine safe minimum |
* Compute machine safe minimum |
* |
* |
SFMIN = DLAMCH('S') |
SFMIN = DLAMCH('S') |
* |
* |
DO 10 J = 1, MIN( M, N ) |
DO 10 J = 1, MIN( M, N ) |
* |
* |
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* |
* |
* Compute elements J+1:M of J-th column. |
* Compute elements J+1:M of J-th column. |
* |
* |
IF( J.LT.M ) THEN |
IF( J.LT.M ) THEN |
IF( ABS(A( J, J )) .GE. SFMIN ) THEN |
IF( ABS(A( J, J )) .GE. SFMIN ) THEN |
CALL DSCAL( M-J, ONE / A( J, J ), A( J+1, J ), 1 ) |
CALL DSCAL( M-J, ONE / A( J, J ), A( J+1, J ), 1 ) |
ELSE |
ELSE |
DO 20 I = 1, M-J |
DO 20 I = 1, M-J |
A( J+I, J ) = A( J+I, J ) / A( J, J ) |
A( J+I, J ) = A( J+I, J ) / A( J, J ) |
20 CONTINUE |
20 CONTINUE |
END IF |
END IF |
END IF |
END IF |
* |
* |
ELSE IF( INFO.EQ.0 ) THEN |
ELSE IF( INFO.EQ.0 ) THEN |
* |
* |