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*> \brief \b SLAMCH
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* REAL FUNCTION SLAMCH( CMACH )
*
* .. Scalar Arguments ..
* CHARACTER CMACH
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLAMCH determines single precision machine parameters.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] CMACH
*> \verbatim
*> Specifies the value to be returned by SLAMCH:
*> = 'E' or 'e', SLAMCH := eps
*> = 'S' or 's , SLAMCH := sfmin
*> = 'B' or 'b', SLAMCH := base
*> = 'P' or 'p', SLAMCH := eps*base
*> = 'N' or 'n', SLAMCH := t
*> = 'R' or 'r', SLAMCH := rnd
*> = 'M' or 'm', SLAMCH := emin
*> = 'U' or 'u', SLAMCH := rmin
*> = 'L' or 'l', SLAMCH := emax
*> = 'O' or 'o', SLAMCH := rmax
*> where
*> eps = relative machine precision
*> sfmin = safe minimum, such that 1/sfmin does not overflow
*> base = base of the machine
*> prec = eps*base
*> t = number of (base) digits in the mantissa
*> rnd = 1.0 when rounding occurs in addition, 0.0 otherwise
*> emin = minimum exponent before (gradual) underflow
*> rmin = underflow threshold - base**(emin-1)
*> emax = largest exponent before overflow
*> rmax = overflow threshold - (base**emax)*(1-eps)
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup auxOTHERauxiliary
*
* =====================================================================
REAL FUNCTION SLAMCH( CMACH )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER CMACH
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ONE, ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* ..
* .. Local Scalars ..
REAL RND, EPS, SFMIN, SMALL, RMACH
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Intrinsic Functions ..
INTRINSIC DIGITS, EPSILON, HUGE, MAXEXPONENT,
$ MINEXPONENT, RADIX, TINY
* ..
* .. Executable Statements ..
*
*
* Assume rounding, not chopping. Always.
*
RND = ONE
*
IF( ONE.EQ.RND ) THEN
EPS = EPSILON(ZERO) * 0.5
ELSE
EPS = EPSILON(ZERO)
END IF
*
IF( LSAME( CMACH, 'E' ) ) THEN
RMACH = EPS
ELSE IF( LSAME( CMACH, 'S' ) ) THEN
SFMIN = TINY(ZERO)
SMALL = ONE / HUGE(ZERO)
IF( SMALL.GE.SFMIN ) THEN
*
* Use SMALL plus a bit, to avoid the possibility of rounding
* causing overflow when computing 1/sfmin.
*
SFMIN = SMALL*( ONE+EPS )
END IF
RMACH = SFMIN
ELSE IF( LSAME( CMACH, 'B' ) ) THEN
RMACH = RADIX(ZERO)
ELSE IF( LSAME( CMACH, 'P' ) ) THEN
RMACH = EPS * RADIX(ZERO)
ELSE IF( LSAME( CMACH, 'N' ) ) THEN
RMACH = DIGITS(ZERO)
ELSE IF( LSAME( CMACH, 'R' ) ) THEN
RMACH = RND
ELSE IF( LSAME( CMACH, 'M' ) ) THEN
RMACH = MINEXPONENT(ZERO)
ELSE IF( LSAME( CMACH, 'U' ) ) THEN
RMACH = tiny(zero)
ELSE IF( LSAME( CMACH, 'L' ) ) THEN
RMACH = MAXEXPONENT(ZERO)
ELSE IF( LSAME( CMACH, 'O' ) ) THEN
RMACH = HUGE(ZERO)
ELSE
RMACH = ZERO
END IF
*
SLAMCH = RMACH
RETURN
*
* End of SLAMCH
*
END
************************************************************************
*> \brief \b SLAMC3
*> \details
*> \b Purpose:
*> \verbatim
*> SLAMC3 is intended to force A and B to be stored prior to doing
*> the addition of A and B , for use in situations where optimizers
*> might hold one of these in a register.
*> \endverbatim
*> \author LAPACK is a software package provided by Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..
*> \date November 2011
*> \ingroup auxOTHERauxiliary
*>
*> \param[in] A
*> \verbatim
*> \endverbatim
*>
*> \param[in] B
*> \verbatim
*> The values A and B.
*> \endverbatim
*>
*
REAL FUNCTION SLAMC3( A, B )
*
* -- LAPACK auxiliary routine (version 3.4.0) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* November 2010
*
* .. Scalar Arguments ..
REAL A, B
* ..
* =====================================================================
*
* .. Executable Statements ..
*
SLAMC3 = A + B
*
RETURN
*
* End of SLAMC3
*
END
*
************************************************************************
|
