LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

Go to the source code of this file.
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 
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.
[in]  A  
[in]  B  The values A and B. 
Definition at line 642 of file dlamchf77.f.
subroutine dlamc4  (  integer  EMIN, 
double precision  START,  
integer  BASE  
) 
DLAMC4
Purpose:
DLAMC4 is a service routine for DLAMC2.
[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.
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 floatingpoint 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.
[in]  BETA  The base of floatingpoint arithmetic. 
[in]  P  The number of base BETA digits in the mantissa of a floatingpoint 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 floatingpoint number. 
Definition at line 796 of file dlamchf77.f.