Numpy 初探SymPy配置|极客教程

初探SymPy配置，IPython中包含一个SymPy配置的样本。SymPy是一个Python的符号计算库。例如，我们可以利用SymPy来化简代数表达式或做微分运算，其功能类似于Mathematica和Maple。显然SymPy是一个有趣的软件，但它不是我们学习NumPy的过程中必须要了解的内容。可以认为本节是一个可选的、有奖励性质的攻略。就像餐后甜点一样，你可以放心地跳过本节，虽然这样做有可能让你错过本章最美妙的一段内容。

准备工作

使用easy_install或pip安装SymPy：

easy_install sympy
sudo pip install sympy

具体步骤

浏览配置文件，其所在位置是~/.ipython/profile_sympy/ipython_config.py。具体内容如下。

c = get_config()
app = c.InteractiveShellApp

# This can be used at any point in a config file to load a sub config
# and merge it into the current one.
load_subconfig('ipython_config.py', profile='default')

lines = """
from __future__ import division
from sympy import *
x, y, z, t = symbols('x y z t')
k, m, n = symbols('k m n', integer=True)
f, g, h = symbols('f g h', cls=Function)
"""

# You have to make sure that attributes that are containers already
# exist before using them.  Simple assigning a new list will override
# all previous values.

if hasattr(app, 'exec_lines'):
    app.exec_lines.append(lines)
else:
    app.exec_lines = [lines]

# Load the sympy_printing extension to enable nice printing of sympy expr's.
if hasattr(app, 'extensions'):
    app.extensions.append('sympyprinting')
else:
    app.extensions = ['sympyprinting']