LAPACK  3.4.2 LAPACK: Linear Algebra PACKage
dlamchf77.f File Reference

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## Functions/Subroutines

DOUBLE PRECISION function dlamch (CMACH)
DLAMCH
subroutine dlamc1 (BETA, T, RND, IEEE1)
DLAMC1
subroutine dlamc2 (BETA, T, RND, EPS, EMIN, RMIN, EMAX, RMAX)
DLAMC2
DOUBLE PRECISION function dlamc3 (A, B)
DLAMC3
subroutine dlamc4 (EMIN, START, BASE)
DLAMC4
subroutine dlamc5 (BETA, P, EMIN, IEEE, EMAX, RMAX)
DLAMC5

## 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.```
Parameters:
 [in] A [in] B ` The values A and B.`

Definition at line 642 of file dlamchf77.f.

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 subroutine dlamc4 ( integer EMIN, double precision START, integer BASE )

DLAMC4

Purpose:

` DLAMC4 is a service routine for DLAMC2.`
Parameters:
 [out] EMIN ``` The minimum exponent before (gradual) underflow, computed by setting A = START and dividing by BASE until the previous A can not be recovered.``` [in] START ` The starting point for determining EMIN.` [in] BASE ` The base of the machine.`

Definition at line 689 of file dlamchf77.f.

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 subroutine dlamc5 ( integer BETA, integer P, integer EMIN, logical IEEE, integer EMAX, double precision RMAX )

DLAMC5

Purpose:

``` DLAMC5 attempts to compute RMAX, the largest machine floating-point
number, without overflow.  It assumes that EMAX + abs(EMIN) sum
approximately to a power of 2.  It will fail on machines where this
assumption does not hold, for example, the Cyber 205 (EMIN = -28625,
EMAX = 28718).  It will also fail if the value supplied for EMIN is
too large (i.e. too close to zero), probably with overflow.```
Parameters:
 [in] BETA ` The base of floating-point arithmetic.` [in] P ``` The number of base BETA digits in the mantissa of a floating-point value.``` [in] EMIN ` The minimum exponent before (gradual) underflow.` [in] IEEE ``` A logical flag specifying whether or not the arithmetic system is thought to comply with the IEEE standard.``` [out] EMAX ` The largest exponent before overflow` [out] RMAX ` The largest machine floating-point number.`

Definition at line 796 of file dlamchf77.f.

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