C Library Functions - M_constants (3)
NAME
M_constants(3f) - [M_constants:INTRO] Useful constants
CONTENTS
Synopsis
Description
Universal Constants
Physical Constants
Notes
Example
SYNOPSIS
use M_constants, only : uc ! real128 constants uc%qp%pi uc%qp%gamma uc%qp%e uc%qp%golden_ratio uc%qp%euler! real64 constants uc%dp%pi uc%dp%gamma uc%dp%e uc%dp%golden_ratio uc%dp%euler
! real32 constants uc%sp%pi uc%sp%gamma uc%sp%e uc%sp%golden_ratio uc%sp%euler
use M_constants, only : f ! formats f%all
DESCRIPTION
Useful universal constants, physical constants, formats, ...
e The base of the natural logarithm system. "e" was named in honor of Euler, but is known as Napier’s constant. "euler" gamma The Euler-Mascheroni constant is often denoted by a lower-case Gamma. golden_ratio In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities. so for a > b > 0, (a + b)/ a = a/b where the Greek letter phi often denotes the golden ratio. pi The ratio of the circumference of a circle to the diameter of the circle
PHYSICAL CONSTANTS
"deg_per_rad" "rad_per_deg"
c__m_per_sec Speed of light in a vacuum c__ft_per_sec Speed of light in a vacuum
NOTES
Gamma is defined as
Gamma = limit ( M -> Infinity ) ( Sum ( 1 <= N <= M ) 1 / N ) - Log ( M )
EXAMPLE
Sample program:
program test_universal_constants use M_constants, only : uc, f ! give a local name to a constant real,parameter :: e=uc%sp%e ! universal constant, single-precision, e character(len=*),parameter :: all=f%all! just use it print f%all, ’gamma=’,uc%qp%gamma ! universal constant, quad-precision, gamma print all, ’e=’,e
! or rename it with ASSOCIATE associate (gamma => uc%dp%gamma) print all,’gamma=’,gamma end associate
end program test_universal_constants
| Nemo Release 3.1 | M_constants (3) | July 22, 2023 |
