multi_point_crossover

x_i_new, of_i_new, fit_i_new, neof, report = multi_point_crossover(of_function, parent_0, parent_1, n_dimensions, x_upper, x_lower, none_variable=None)

This function performs the multi point crossover operator. Two new points are generated from the two parent points (offspring).

Input variables

Name	Description	Type
of_function	Objective function	Py function (def)
parent_0	Current design variables of the first parent	List
parent_1	Current design variables of the second parent	List
n_dimensions	Problem dimension	Integer
x_upper	Upper limit of the design variables	List
x_lower	Lower limit of the design variables	List
none_variable	None variable. Default is None. Use in objective function	None, List, Float, Dictionary, String or any

Output variables

Name	Description	Type
x_i_new	Update variables of the i agent	L'ist
of_i_new	Update objective function value of the i agent	Float
fit_i_new	Update fitness value of the i agent	Float
neof	New solution indicator. It is a Boolean value (1 to indicate a new solution)	Integer
report	Report about the crossover process	String

Example 1

from metapy_toolbox import multi_point_crossover

# Data
father1 = [1.7, 3.6, 2.7, 1.5, 1.3]
father2 = [3.9, 1.6, 2.5, 3.2, 3.3]
nDimensions = len(father1)
xUpper = [5, 5, 5, 5, 5]
xLower = [1, 1, 1, 1, 1]
noneVariable = None

# Objective function
def objFunction(x, _):
    """Example objective function"""
    x0 = x[0]
    x1 = x[1]
    of = x0 ** 2 + x1 ** 2
    return of

# Call function
xNew, ofNew, fitNew, neof, report = multi_point_crossover(objFunction, father1, father2, nDimensions, xUpper, xLower, noneVariable)

# Output details
print('x new ', xNew)
print('of new ', ofNew)
print('fit new', fitNew)
print('number of evalutions objective function', neof)

x new  [1.7, 1.6, 1.7, 1.6, 1.7]
of new  5.45
fit new 0.15503875968992248
number of evalutions objective function 2

To check the movement report just apply the following instruction.

# Report details
arq = "report_example.txt"

# Writing report
with open(arq, "w") as file:
    file.write(report)

Open report_example.txt.

    Crossover operator - multi point crossover
    current p0 = [1.7, 3.6, 2.7, 1.5, 1.3]
    current p1 = [3.9, 1.6, 2.5, 3.2, 3.3]
    cut mask = [0, 1, 0, 1, 0]
    offspring a = [1.7, 1.6, 1.7, 1.6, 1.7], of_a = 5.45
    offspring b = [3.9, 3.6, 3.9, 3.6, 3.9], of_b = 28.17
    update pos = [1.7, 1.6, 1.7, 1.6, 1.7], of = 5.45, fit = 0.15503875968992248