version 1.8, 2011/11/21 20:42:56
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version 1.17, 2018/05/29 07:17:57
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*> \brief \b DLANST |
*> \brief \b DLANST returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric tridiagonal 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 DLANST + dependencies |
*> Download DLANST + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlanst.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlanst.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlanst.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlanst.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlanst.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlanst.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* DOUBLE PRECISION FUNCTION DLANST( NORM, N, D, E ) |
* DOUBLE PRECISION FUNCTION DLANST( NORM, N, D, E ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* CHARACTER NORM |
* CHARACTER NORM |
* INTEGER N |
* INTEGER N |
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* .. Array Arguments .. |
* .. Array Arguments .. |
* DOUBLE PRECISION D( * ), E( * ) |
* DOUBLE PRECISION D( * ), E( * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \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 December 2016 |
* |
* |
*> \ingroup auxOTHERauxiliary |
*> \ingroup OTHERauxiliary |
* |
* |
* ===================================================================== |
* ===================================================================== |
DOUBLE PRECISION FUNCTION DLANST( NORM, N, D, E ) |
DOUBLE PRECISION FUNCTION DLANST( NORM, N, D, E ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK auxiliary routine (version 3.7.0) -- |
* -- 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 |
* December 2016 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
CHARACTER NORM |
CHARACTER NORM |
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DOUBLE PRECISION ANORM, SCALE, SUM |
DOUBLE PRECISION ANORM, SCALE, SUM |
* .. |
* .. |
* .. External Functions .. |
* .. External Functions .. |
LOGICAL LSAME |
LOGICAL LSAME, DISNAN |
EXTERNAL LSAME |
EXTERNAL LSAME, DISNAN |
* .. |
* .. |
* .. External Subroutines .. |
* .. External Subroutines .. |
EXTERNAL DLASSQ |
EXTERNAL DLASSQ |
* .. |
* .. |
* .. Intrinsic Functions .. |
* .. Intrinsic Functions .. |
INTRINSIC ABS, MAX, SQRT |
INTRINSIC ABS, SQRT |
* .. |
* .. |
* .. Executable Statements .. |
* .. Executable Statements .. |
* |
* |
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* |
* |
ANORM = ABS( D( N ) ) |
ANORM = ABS( D( N ) ) |
DO 10 I = 1, N - 1 |
DO 10 I = 1, N - 1 |
ANORM = MAX( ANORM, ABS( D( I ) ) ) |
SUM = ABS( D( I ) ) |
ANORM = MAX( ANORM, ABS( E( I ) ) ) |
IF( ANORM .LT. SUM .OR. DISNAN( SUM ) ) ANORM = SUM |
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SUM = ABS( E( I ) ) |
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IF( ANORM .LT. SUM .OR. DISNAN( SUM ) ) ANORM = SUM |
10 CONTINUE |
10 CONTINUE |
ELSE IF( LSAME( NORM, 'O' ) .OR. NORM.EQ.'1' .OR. |
ELSE IF( LSAME( NORM, 'O' ) .OR. NORM.EQ.'1' .OR. |
$ LSAME( NORM, 'I' ) ) THEN |
$ LSAME( NORM, 'I' ) ) THEN |
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IF( N.EQ.1 ) THEN |
IF( N.EQ.1 ) THEN |
ANORM = ABS( D( 1 ) ) |
ANORM = ABS( D( 1 ) ) |
ELSE |
ELSE |
ANORM = MAX( ABS( D( 1 ) )+ABS( E( 1 ) ), |
ANORM = ABS( D( 1 ) )+ABS( E( 1 ) ) |
$ ABS( E( N-1 ) )+ABS( D( N ) ) ) |
SUM = ABS( E( N-1 ) )+ABS( D( N ) ) |
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IF( ANORM .LT. SUM .OR. DISNAN( SUM ) ) ANORM = SUM |
DO 20 I = 2, N - 1 |
DO 20 I = 2, N - 1 |
ANORM = MAX( ANORM, ABS( D( I ) )+ABS( E( I ) )+ |
SUM = ABS( D( I ) )+ABS( E( I ) )+ABS( E( I-1 ) ) |
$ ABS( E( I-1 ) ) ) |
IF( ANORM .LT. SUM .OR. DISNAN( SUM ) ) ANORM = SUM |
20 CONTINUE |
20 CONTINUE |
END IF |
END IF |
ELSE IF( ( LSAME( NORM, 'F' ) ) .OR. ( LSAME( NORM, 'E' ) ) ) THEN |
ELSE IF( ( LSAME( NORM, 'F' ) ) .OR. ( LSAME( NORM, 'E' ) ) ) THEN |