Equation Interpeter¶
The Equation Package provide an extentable Equation Parser and Evaluation System.
It will take a string such as “sin(x+y^2)” and convert it to a python object that can be called this allow the safe evaluation of equations stored in configuration files or enterned from the keyboard. This Package never calls a python evaluation command hence their is no risk of executing any unexpected python code.
The Generated Expression Object is desgined to behave like a python function, and can be used any where a python funcion is expected, it may be called with either positional or keyword arguments to set the Equations Variables, by default the order of the variables is as they appear in the equation, however an explicit order may be set when the Expression object is created.
Example¶
>>> from Equation import Expression
>>> fn = Expression("sin(x+y^2)",["y","x"])
>>> fn
sin((x + (y ^ (2+0j))))
>>> print fn
\sin\left(\left(x + y^{(2+0j)}\right)\right)
>>> fn(3,4)
(0.42016703682664092+0j)
Numpy Arrays Supported¶
The default function maping used by this package map the operators and functions to Numpy Functions, hence the generated object may be called with numpy arrays.
Latex Support¶
The display string format i.e. str() is set to use Latex syntax allowing high quality equations to be rendered in output this syntax is supported by the grqaphing package matplotlib
Note
repr() method will return a string suitable for passing to Expression, however it is recalucated from the tokenized expression, and has all brackets.
Future Versions¶
Goals for future versions are:
- Reduce repr() type respresentation to use only required brackets
- Allow the use of function variable, rather than just predefined functions
License¶
Copyright 2014 AlphaOmega Technology
Licensed under the AlphaOmega Technology Open License Version 1.0 You may not use this file except in compliance with this License. You may obtain a copy of the License at
