calculus

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== Calculus

Calculus is utility library which allow to parse some subset of latex equations and store them in {Postfix notation}[http://en.wikipedia.org/wiki/Reverse_Polish_notation] It also allows translate it to {Abstract syntax tree}[http://en.wikipedia.org/wiki/Abstract_syntax_tree] and calculate (implemented for simple expressions).

Build status: {}[http://travis-ci.org/avsej/calculus]

== Installation

gem install calculus

== Examples

001:0> require 'calculus' true 002:0> exp = Calculus::Expression.new("2 + 3 * x") #<Expression:f46e77a9377ed2d5a9da768496a7e1c20be51bfe postfix_notation=[2, 3, "x", :mul, :plus] variables={"x"=>nil}> 003:0> exp.postfix_notation [2, 3, "x", :mul, :plus] 004:0> exp.abstract_syntax_tree [:plus, 2, [:mul, 3, "x"]] 005:0> exp.variables ["x"] 006:0> exp.unbound_variables ["x"] 007:0> exp["x"] = 5 5 008:0> exp.unbound_variables [] 009:0> exp.calculate 17

You can also render expression to PNG image if you have latex and dvipng installed.

010:0> Calculus::Expression.new("2 + 3 \cdot x").to_png "/tmp/d20110512-16457-dhxt71/f46e77a9377ed2d5a9da768496a7e1c20be51bfe.png"

{2 + 3 \cdot x}[http://files.avsej.net/exp1.png]

Also you can skip parser if you need only png generation 011:0> Calculus::Expression.new("\hat{f}(\xi) = \int_{-\infty}^{\infty} f(x)\ e^{- 2\pi i x \xi}\,dx", :parse => false).to_png

{\hat{f}(\xi) = \int_{-\infty}^{\infty} f(x)\ e^{- 2\pi i x \xi},dx}[http://files.avsej.net/exp2.png]

Don't forget to cleanup file after using.

== Hacking

Just fork and pull request.