stdlib_constants:local:
:depth: 2
The stdlib_constants module provides mathematical constants and the most common physical constants.
Warning: The names of the most common physical constants are kept short as they are inside a dedicated module. Nonetheless, in case of overlapping names, they can always be renamed as following:
use stdlib_constants, only: clight => c
The stdlib_codata module defines all codata (physical) constants as derived
type. The module is automatically generated with a simple
parser written in Python
The latest codata constants were released in 2022 by the NIST
All values for the codata constants are provided as double precision reals.
The names are quite long and can be aliased with shorter names.
The derived type codata_constant_type defines:
4 members:
name (string)value (double precision real)uncertainty (double precision real)unit (string)2 type-bound procedures:
print: to print the values of the constant members;to_real: to get the value or the uncertainty to the desired precision.A module level interface to_real is
available for getting the constant value or uncertainty of a constant.
to_real - Get the constant value or its uncertainty.Experimental
Convert a codata_constant_type to a real (at least sp, or dp) scalar.
Warning: Some constants cannot be converted to single precision sp reals due to the value of the exponents.
r = to_real (c, mold [, uncertainty])
c: argument has intent(in) and shall be of type codata_constant_type.
mold: argument has intent(in) and shall be of real type.
Note: The type of the mold argument defines the type of the result.
uncertainty (optional): argument has intent(in) and shall be of logical type.
It specifies if the uncertainty needs to be returned instead of the value. Default to .false..
Returns a scalar of real type which is either the value or the uncertainty of a codata constant.
{literalinclude} ../../example/constants/example_constants.f90
:language: fortran