info.py :  » Database » PyTables » tables-2.1.2 » tables » numexpr » Python Open Source

Home
Python Open Source
1.3.1.2 Python
2.Ajax
3.Aspect Oriented
4.Blog
5.Build
6.Business Application
7.Chart Report
8.Content Management Systems
9.Cryptographic
10.Database
11.Development
12.Editor
13.Email
14.ERP
15.Game 2D 3D
16.GIS
17.GUI
18.IDE
19.Installer
20.IRC
21.Issue Tracker
22.Language Interface
23.Log
24.Math
25.Media Sound Audio
26.Mobile
27.Network
28.Parser
29.PDF
30.Project Management
31.RSS
32.Search
33.Security
34.Template Engines
35.Test
36.UML
37.USB Serial
38.Web Frameworks
39.Web Server
40.Web Services
41.Web Unit
42.Wiki
43.Windows
44.XML
Python Open Source » Database » PyTables 
PyTables » tables 2.1.2 » tables » numexpr » info.py
"""Fast numerical expression evaluator

Usage:

The easiest way is to use the ``evaluate`` function:

>>> a = numpy.array([1., 2, 3])
>>> b = numpy.array([4, 5, 6])
>>> c = numpy.array([7., 8, 9])
>>> numexpr.evaluate("2.0 * a + 3 * b * c")
array([  86.,  124.,  168.])

This works for every datatype defined in NumPy and the next operators
are supported:

    Logical operators: &, |, ~
    Comparison operators: <, <=, ==, !=, >=, >
    Unary arithmetic operators: -
    Binary arithmetic operators: +, -, *, /, **, %

Note: Types do not support all operators. Boolean values only support
    logical and strict (in)equality comparison operators, while
    strings only support comparisons, numbers do not work with logical
    operators, and complex comparisons can only check for strict
    (in)equality. Unsupported operations (including invalid castings)
    raise NotImplementedError exceptions.

The next functions are also supported:

    where(bool, number1, number2): number - number1 if the bool
    condition is true, number2 otherwise.

    {sin,cos,tan}(float|complex): float|complex - trigonometric sine,
    cosine or tangent.

    {arcsin,arccos,arctan}(float|complex): float|complex -
    trigonometric inverse sine, cosine or tangent.

    arctan2(float1, float2): float - trigonometric inverse tangent of
    float1/float2.

    {sinh,cosh,tanh}(float|complex): float|complex - hyperbolic sine,
    cosine or tangent.

    {arcsinh,arccosh,arctanh}(float|complex): float|complex -
    hyperbolic inverse sine, cosine or tangent.

    {log,log10,log1p}(float|complex): float|complex</literal> -
    natural, base-10 and log(1+x) logarithms.

    {exp,expm1}(float|complex): float|complex</literal> - exponential
    and exponential minus one.

    sqrt(float|complex): float|complex - square root.

    {real,imag}(complex): float - real or imaginary part of complex.

    complex(float, float): complex - complex from real and imaginary
    parts.


Copyright 2006,2007 David M. Cooke <cookedm@physics.mcmaster.ca>
Licenced under a BSD-style license. See LICENSE.txt in the scipy source
directory.
"""

depends = ['core', 'testing']
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.