cbx.objectives.Rosenbrock

class cbx.objectives.Rosenbrock(a=1.0, b=100.0)

Bases: cbx_objective

Rosenbrock’s function

Rosenbrock’s function is a multimodal function with a global minimum at \((1,1)\). The function is defined as

\[f(x,y) = (a-x)^2 + b(y-x^2)^2\]

See Rosenbrock’s function.

Parameters:

• a (float, optional) – The first parameter of the function. The default is 1.0.

• b (float, optional) – The second parameter of the function. The default is 100.0.

Examples

>>> import numpy as np
>>> from cbx.objectives import Rosenbrock
>>> x = np.array([[1,2], [3,4], [5,6]])
>>> f = Rosenbrock()
>>> f(x)
array([  0.,  76.,  76.])

Visualization

(Source code, png, hires.png, pdf)