Provided by: liblapack-doc_3.12.0-3build1.1_all
NAME
lamch - lamch: machine parameters
SYNOPSIS
Functions double precision function dlamch (cmach) DLAMCH real function slamch (cmach) SLAMCH
Detailed Description
Function Documentation
double precision function dlamch (character cmach) DLAMCH Purpose: DLAMCH determines double precision machine parameters. Parameters CMACH CMACH is 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) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. real function slamch (character cmach) SLAMCH Purpose: SLAMCH determines single precision machine parameters. Parameters CMACH CMACH is CHARACTER*1 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) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.
Author
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