1DLAMCH(1)           LAPACK auxiliary routine (version 3.2)           DLAMCH(1)
2
3
4

NAME

6       DLAMCH - double precision machine parameters
7

SYNOPSIS

9       DOUBLE PRECISION FUNCTION DLAMCH( CMACH )
10
11           CHARACTER    CMACH
12

PURPOSE

14       DLAMCH determines double precision machine parameters.
15
16

ARGUMENTS

18       CMACH   (input) CHARACTER*1
19               Specifies the value to be returned by DLAMCH:
20               = 'E' or 'e',   DLAMCH := eps
21               = 'S' or 's ,   DLAMCH := sfmin
22               = 'B' or 'b',   DLAMCH := base
23               = 'P' or 'p',   DLAMCH := eps*base
24               = 'N' or 'n',   DLAMCH := t
25               = 'R' or 'r',   DLAMCH := rnd
26               = 'M' or 'm',   DLAMCH := emin
27               = 'U' or 'u',   DLAMCH := rmin
28               = 'L' or 'l',   DLAMCH := emax
29               = 'O' or 'o',   DLAMCH := rmax
30
31               where
32
33       eps   = relative machine precision
34             sfmin = safe minimum, such that 1/sfmin does not overflow base  =
35             base of the machine prec  = eps*base t      =  number  of  (base)
36             digits  in the mantissa rnd   = 1.0 when rounding occurs in addi‐
37             tion, 0.0 otherwise emin  =  minimum  exponent  before  (gradual)
38             underflow  rmin   =  underflow threshold - base**(emin-1) emax  =
39             largest exponent before overflow rmax  =  overflow  threshold   -
40             (base**emax)*(1-eps)
41
42
43
44 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       DLAMCH(1)