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SRC/lapack_64_obj/dlamch.f(3) Library Functions Manual SRC/lapack_64_obj/dlamch.f(3)

NAME

SRC/lapack_64_obj/dlamch.f

SYNOPSIS

Functions/Subroutines


double precision function DLAMCH (cmach)
DLAMCH double precision function DLAMC3 (a, b)
DLAMC3

Function/Subroutine Documentation

double precision function DLAMC3 (double precision a, double precision b)

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..

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.

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.

Definition at line 69 of file dlamch.f.

Author

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Version 3.12.1 LAPACK