DLAMCH(3)

NAME
DLAMCH - double precision machine parameters

SYNOPSIS

DOUBLE PRECISION
    FUNCTION DLAMCH( CMACH )

CHARACTER
    CMACH

PURPOSE
DLAMCH determines double precision machine parameters.

ARGUMENTS

CMACH   (input) CHARACTER*1
    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)