Prev

Next

Index-> contents reference index search external

Up-> f2cad utility d1mach

f2cad-> license Install get_started prototype library run.cpp utility add2lib.sh whats_new

utility-> i1mach d1mach f2cad_link near_equal xerror2cpp

d1mach

Headings-> Syntax Purpose i d Mapping

Implementation of Cmlib d1mach Routine in Cpp
Syntax
d = d1mach_(i)

Purpose
This routine uses the C++ standard numeric_limits to implement the specifications required by the cmlib Fortran routine d1mach.

i
The argument i has prototype
     integer* i
It specifies which machine constant to evaluate.

d
The return value d has prototype % doublereal %d% % and is the value of the requested machine constant.

Mapping
The Fortran definition for the machine constants below was extracted from the comments in the Fortran routine d1mach. The C++ definitions were extracted from the numeric_limits section of the C++ standard.

i	d
1	B**(EMIN-1), the smallest positive magnitude.
2	B**EMAX*(1 - B**(-T)), the largest magnitude.
3	B**(-T), the smallest relative spacing.
4	B**(1-T), the largest relative spacing.
5	LOG10(B).

---

Input File: lib/d1mach.cpp