Dlamch.f -
double precision function dlamch (CMACH)
DLAMCH double precision function dlamc3 (A, B)
DLAMC3
DLAMC3 Purpose:
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.
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
Parameters:
A
A is a DOUBLE PRECISION
B
B is a DOUBLE PRECISION
The values A and B.
Definition at line 172 of file dlamch.f.
DLAMCH
Purpose:
DLAMCH determines double precision machine parameters.
Parameters:
CMACH
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)
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 64 of file dlamch.f.
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