scipy求解非线性方程组example

scipy求解非线性方程组

scipy.optimize.root 函数参数不太明白，找到目录下说明示例，可得二元非线性方程组解法。

Examples
--------
The following functions define a system of nonlinear equations and its
jacobian.

>>> def fun(x):
...     return [x[0]  + 0.5 * (x[0] - x[1])**3 - 1.0,
...             0.5 * (x[1] - x[0])**3 + x[1]]

>>> def jac(x):
...     return np.array([[1 + 1.5 * (x[0] - x[1])**2,
...                       -1.5 * (x[0] - x[1])**2],
...                      [-1.5 * (x[1] - x[0])**2,
...                       1 + 1.5 * (x[1] - x[0])**2]])

A solution can be obtained as follows.

>>> from scipy import optimize
>>> sol = optimize.root(fun, [0, 0], jac=jac, method='hybr')
>>> sol.x
array([ 0.8411639,  0.1588361])
"""

import numpy as np

#解非线性方程组

    
def fun(x):
    return [x[0]  + 0.5 *