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103 lines
2.4 KiB
103 lines
2.4 KiB
2 years ago
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*> \brief \b DGET06
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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* Definition:
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* ===========
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*
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* DOUBLE PRECISION FUNCTION DGET06( RCOND, RCONDC )
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*
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* .. Scalar Arguments ..
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* DOUBLE PRECISION RCOND, RCONDC
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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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*> DGET06 computes a test ratio to compare two values for RCOND.
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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] RCOND
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*> \verbatim
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*> RCOND is DOUBLE PRECISION
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*> The estimate of the reciprocal of the condition number of A,
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*> as computed by DGECON.
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*> \endverbatim
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*>
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*> \param[in] RCONDC
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*> \verbatim
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*> RCONDC is DOUBLE PRECISION
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*> The reciprocal of the condition number of A, computed as
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*> ( 1/norm(A) ) / norm(inv(A)).
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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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*
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*> \ingroup double_lin
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*
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* =====================================================================
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DOUBLE PRECISION FUNCTION DGET06( RCOND, RCONDC )
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*
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* -- LAPACK test routine --
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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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*
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* .. Scalar Arguments ..
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DOUBLE PRECISION RCOND, RCONDC
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* ..
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*
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* =====================================================================
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*
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* .. Parameters ..
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DOUBLE PRECISION ZERO, ONE
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PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 )
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* ..
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* .. Local Scalars ..
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DOUBLE PRECISION EPS, RAT
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* ..
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* .. External Functions ..
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DOUBLE PRECISION DLAMCH
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EXTERNAL DLAMCH
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* ..
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* .. Intrinsic Functions ..
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INTRINSIC MAX, MIN
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* ..
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* .. Executable Statements ..
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*
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EPS = DLAMCH( 'Epsilon' )
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IF( RCOND.GT.ZERO ) THEN
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IF( RCONDC.GT.ZERO ) THEN
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RAT = MAX( RCOND, RCONDC ) / MIN( RCOND, RCONDC ) -
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$ ( ONE-EPS )
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ELSE
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RAT = RCOND / EPS
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END IF
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ELSE
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IF( RCONDC.GT.ZERO ) THEN
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RAT = RCONDC / EPS
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ELSE
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RAT = ZERO
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END IF
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END IF
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DGET06 = RAT
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RETURN
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*
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* End of DGET06
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*
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END
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