How to solve a pair of nonlinear equations using Python?

python numpy scipy sympy
AIB picture AIB · Jan 5, 2012 · Viewed 99.9k times · Source

What's the (best) way to solve a pair of non linear equations using Python. (Numpy, Scipy or Sympy)

eg:

  • x+y^2 = 4
  • e^x+ xy = 3

A code snippet which solves the above pair will be great

Answer

HYRY picture HYRY · Jan 5, 2012

for numerical solution, you can use fsolve:

http://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.fsolve.html#scipy.optimize.fsolve

from scipy.optimize import fsolve
import math

def equations(p):
    x, y = p
    return (x+y**2-4, math.exp(x) + x*y - 3)

x, y =  fsolve(equations, (1, 1))

print equations((x, y))

Related questions

plus/minus operator for python ±

I am looking for a way to do a plus/minus operation in python 2 or 3. I do not know the command or operator, and I cannot find a command or operator to do this. Am I missing something?

Read More
Any way to solve a system of coupled differential equations in python?

I've been working with sympy and scipy, but can't find or figure out how to solve a system of coupled differential equations (non-linear, first-order). So is there any way to solve coupled differential equations? The equations are of the form: …

Read More
How to perform non-linear optimization with scipy/numpy or sympy?

I am trying to find the optimal solution to the follow system of equations in Python: (x-x1)^2 + (y-y1)^2 - r1^2 = 0 (x-x2)^2 + (y-y2)^2 - r2^2 = 0 (x-x3)^2 + (y-y3)^2 - r3^2 = 0 Given the values a point(x,y) and a radius (r): x1, …

Read More