Physics Calculator

a command-line unit-conscious scientific calculator

• Version: 0.1.0
• Author: Yuto Ichinohe

Introduction

Physics Calculator is a simple command-line scientific calculator which is useful especially for the researchers/students engaged in natural science/engineering etc...

Features

Unit-conscious calculation

[MKSA]> 1[km]/1[sec]
1000.0 m s-1

Scientific constants

[MKSA]> G
6.67384e-11 m3 kg-1 s-2

Mathematical funcions

[MKSA]> cos(pi)
-1.0

Use of multiple unit systems

[MKSA]> q
1.60217657e-19 s A // elementary charge in MKSA
[MKSA]> :us
unit system [MKSA, CGS]> cgs
[CGS]> q
4.80320452070309e-10 cm3/2 g1/2 s-1 // elementary charge in CGS

Use of local variables

 [MKSA]> a=2[km]
 a is set to 2000.0 m
 [MKSA]> a*5
 10000.0 m

Load forms from a file

 [MKSA]> :l forms.txt // a=2[km]
 a is set to 2000.0 m
 [MKSA]> a*2
 4000.0 m

• Yuto Ichinohe
• ISAS/JAXA, University of Tokyo
• yutoichinohe(AT)gmail.com

GitHub

https://github.com/yutoichinohe/PhysicsCalculator

Installation

Required Software

(1) Ruby

(2) Parslet

Installation Guide

(1) Install Parslet

$ gem install parslet

(2) Obtain the source

$ git clone https://github.com/yutoichinohe/PhysicsCalculator.git

Usage

Get Started

Using REPL

$ ./Calculator.rb
[MKSA]> 180[km]/20[sec] // unit-conscious calculation
9000.0 m s-1
[MKSA]> 250[kpc]/1000[km/s]=?Myr // print results in a specific unit
244.4532762791914 [Myr]
[MKSA]> G*5.972e24[kg]/6371[km]**2 // use of physical constant
9.819296622997971 m s-2
[MKSA]> cos((250[min]+3[hr])/2.5e4[sec])**ln(e*1[m]/1000[mm]) // mathematical function
0.5131032184972966
[MKSA]> q^2/4/pi/epsilon0/hbar/c // fine structure constant in MKSA
0.0072973526210695135
[MKSA]> :us // different unit system
unit system [MKSA, CGS]> cgs
[CGS]> q^2/hbar/c
0.007297352621069511 // fine structure constant in CGS
[CGS]> :mksa
[MKSA]> a = 2*G*M_sun/c**2 // set "a" as the Schwarzschild radius of the Sun
a is set to 2954.07146641595 m
[MKSA]> a =? km
2.95407146641595 [km]
[MKSA]> a / 3000[m]
0.9846904888053166
[MKSA]> c0=2 // you cannot overwrite previously defined constants
"c0" - already defined as a constant
[MKSA]> :q
Bye

From command-line

$ ./Calculator.rb 1[eV] =? J
1.60217657e-19 [J]

Commands

.q, .e, :q, :e, quit, exit, Ctrl-c -- quit
.h, :h, help -- show help
.l, :l, load -- load forms from a file
.us, :us, unitsystem -- change unit system
.c, :c, const -- print available constants
.u, :u, unit -- print available units
.f, :f, func -- print available functions

Syntax

• Available operators
  addition (+), subtraction (-), multiplication (*), division (/), power (**, ^)
• The scientific notation of numbers is allowed.
  ex.) -2e3, -2.0e3, -2E3 => -2000.0
• Use [] to describe units.
  ex.) 20[km**2/sec], 20[km^2 sec-1], 20[km 2 sec -1] => 20000000.0 m2 s-1
• Use =? to convert the result into a specific unit.
  ex.) 20[m]=?km, 20[m] =? [km] => 0.02 [km]
• Constants are inputted directly.
  ex.) c => 299792458.0 m s-1, q => 1.60217657e-19 s A
• Units can also be used as constants.
  ex.) km => 1000.0 m
• Functions are inputted with ().
  ex.) sin(2.0), sin(1+1), sin(2[m]/1[m]) => 0.9092974268256817
• Use = to define a local variable.
  ex.) a=20[m] => a is set to 2.0 m