numeric-linalg
Educational material on the SciPy implementation of numerical linear algebra algorithms
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| lapack/TESTING/LIN/dget06.f | 2423B | -rw-r--r-- |
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*> \brief \b DGET06 * * =========== DOCUMENTATION =========== * * Online html documentation available at * http://www.netlib.org/lapack/explore-html/ * * Definition: * =========== * * DOUBLE PRECISION FUNCTION DGET06( RCOND, RCONDC ) * * .. Scalar Arguments .. * DOUBLE PRECISION RCOND, RCONDC * .. * * *> \par Purpose: * ============= *> *> \verbatim *> *> DGET06 computes a test ratio to compare two values for RCOND. *> \endverbatim * * Arguments: * ========== * *> \param[in] RCOND *> \verbatim *> RCOND is DOUBLE PRECISION *> The estimate of the reciprocal of the condition number of A, *> as computed by DGECON. *> \endverbatim *> *> \param[in] RCONDC *> \verbatim *> RCONDC is DOUBLE PRECISION *> The reciprocal of the condition number of A, computed as *> ( 1/norm(A) ) / norm(inv(A)). *> \endverbatim * * Authors: * ======== * *> \author Univ. of Tennessee *> \author Univ. of California Berkeley *> \author Univ. of Colorado Denver *> \author NAG Ltd. * *> \ingroup double_lin * * ===================================================================== DOUBLE PRECISION FUNCTION DGET06( RCOND, RCONDC ) * * -- LAPACK test routine -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- * * .. Scalar Arguments .. DOUBLE PRECISION RCOND, RCONDC * .. * * ===================================================================== * * .. Parameters .. DOUBLE PRECISION ZERO, ONE PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) * .. * .. Local Scalars .. DOUBLE PRECISION EPS, RAT * .. * .. External Functions .. DOUBLE PRECISION DLAMCH EXTERNAL DLAMCH * .. * .. Intrinsic Functions .. INTRINSIC MAX, MIN * .. * .. Executable Statements .. * EPS = DLAMCH( 'Epsilon' ) IF( RCOND.GT.ZERO ) THEN IF( RCONDC.GT.ZERO ) THEN RAT = MAX( RCOND, RCONDC ) / MIN( RCOND, RCONDC ) - $ ( ONE-EPS ) ELSE RAT = RCOND / EPS END IF ELSE IF( RCONDC.GT.ZERO ) THEN RAT = RCONDC / EPS ELSE RAT = ZERO END IF END IF DGET06 = RAT RETURN * * End of DGET06 * END