LAPACK
3.4.2
LAPACK: Linear Algebra PACKage
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Go to the source code of this file.
Functions/Subroutines | |
REAL function | slamch (CMACH) |
SLAMCH | |
subroutine | slamc1 (BETA, T, RND, IEEE1) |
SLAMC1 | |
subroutine | slamc2 (BETA, T, RND, EPS, EMIN, RMIN, EMAX, RMAX) |
SLAMC2 | |
REAL function | slamc3 (A, B) |
SLAMC3 | |
subroutine | slamc4 (EMIN, START, BASE) |
SLAMC4 | |
subroutine | slamc5 (BETA, P, EMIN, IEEE, EMAX, RMAX) |
SLAMC5 |
REAL function slamc3 | ( | real | A, |
real | B | ||
) |
SLAMC3
Purpose:
SLAMC3 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 646 of file slamchf77.f.
subroutine slamc4 | ( | integer | EMIN, |
real | START, | ||
integer | BASE | ||
) |
SLAMC4
Purpose:
SLAMC4 is a service routine for SLAMC2.
[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 693 of file slamchf77.f.
subroutine slamc5 | ( | integer | BETA, |
integer | P, | ||
integer | EMIN, | ||
logical | IEEE, | ||
integer | EMAX, | ||
real | RMAX | ||
) |
SLAMC5
Purpose:
SLAMC5 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.
[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 801 of file slamchf77.f.