| *> \brief \b DLAMCH |
| * |
| * =========== DOCUMENTATION =========== |
| * |
| * Online html documentation available at |
| * http://www.netlib.org/lapack/explore-html/ |
| * |
| * Definition: |
| * =========== |
| * |
| * DOUBLE PRECISION FUNCTION DLAMCH( CMACH ) |
| * |
| * |
| *> \par Purpose: |
| * ============= |
| *> |
| *> \verbatim |
| *> |
| *> DLAMCH determines double precision machine parameters. |
| *> \endverbatim |
| * |
| * Arguments: |
| * ========== |
| * |
| *> \param[in] CMACH |
| *> \verbatim |
| *> Specifies the value to be returned by DLAMCH: |
| *> = 'E' or 'e', DLAMCH := eps |
| *> = 'S' or 's , DLAMCH := sfmin |
| *> = 'B' or 'b', DLAMCH := base |
| *> = 'P' or 'p', DLAMCH := eps*base |
| *> = 'N' or 'n', DLAMCH := t |
| *> = 'R' or 'r', DLAMCH := rnd |
| *> = 'M' or 'm', DLAMCH := emin |
| *> = 'U' or 'u', DLAMCH := rmin |
| *> = 'L' or 'l', DLAMCH := emax |
| *> = 'O' or 'o', DLAMCH := 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 |
| * |
| * ===================================================================== |
| DOUBLE PRECISION FUNCTION DLAMCH( 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 .. |
| DOUBLE PRECISION ONE, ZERO |
| PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 ) |
| * .. |
| * .. Local Scalars .. |
| DOUBLE PRECISION 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 |
| * |
| DLAMCH = RMACH |
| RETURN |
| * |
| * End of DLAMCH |
| * |
| END |
| ************************************************************************ |
| *> \brief \b DLAMC3 |
| *> \details |
| *> \b Purpose: |
| *> \verbatim |
| *> DLAMC3 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 |
| *> A is a DOUBLE PRECISION |
| *> \endverbatim |
| *> |
| *> \param[in] B |
| *> \verbatim |
| *> B is a DOUBLE PRECISION |
| *> The values A and B. |
| *> \endverbatim |
| *> |
| DOUBLE PRECISION FUNCTION DLAMC3( A, B ) |
| * |
| * -- LAPACK auxiliary routine (version 3.4.0) -- |
| * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. |
| * November 2010 |
| * |
| * .. Scalar Arguments .. |
| DOUBLE PRECISION A, B |
| * .. |
| * ===================================================================== |
| * |
| * .. Executable Statements .. |
| * |
| DLAMC3 = A + B |
| * |
| RETURN |
| * |
| * End of DLAMC3 |
| * |
| END |
| * |
| ************************************************************************ |
