test_global_optimization.py

from dlib import find_max_global, find_min_global
import dlib
from pytest import raises
from math import sin,cos,pi,exp,sqrt,pow


def test_global_optimization_nargs():
    w0 = find_max_global(lambda *args: sum(args), [0, 0, 0], [1, 1, 1], 10)
    w1 = find_min_global(lambda *args: sum(args), [0, 0, 0], [1, 1, 1], 10)
    assert w0 == ([1, 1, 1], 3)
    assert w1 == ([0, 0, 0], 0)

    w2 = find_max_global(lambda a, b, c, *args: a + b + c - sum(args), [0, 0, 0], [1, 1, 1], 10)
    w3 = find_min_global(lambda a, b, c, *args: a + b + c - sum(args), [0, 0, 0], [1, 1, 1], 10)
    assert w2 == ([1, 1, 1], 3)
    assert w3 == ([0, 0, 0], 0)

    with raises(Exception):
        find_max_global(lambda a, b: 0, [0, 0, 0], [1, 1, 1], 10)
    with raises(Exception):
        find_min_global(lambda a, b: 0, [0, 0, 0], [1, 1, 1], 10)
    with raises(Exception):
        find_max_global(lambda a, b, c, d, *args: 0, [0, 0, 0], [1, 1, 1], 10)
    with raises(Exception):
        find_min_global(lambda a, b, c, d, *args: 0, [0, 0, 0], [1, 1, 1], 10)


def F(a,b):
    return -pow(a-2,2.0) - pow(b-4,2.0);
def G(x):
    return 2-pow(x-5,2.0); 

def test_global_function_search():
    spec_F = dlib.function_spec([-10,-10], [10,10])
    spec_G = dlib.function_spec([-2], [6])

    opt = dlib.global_function_search([spec_F, spec_G])

    for i in range(15):
        next = opt.get_next_x()
        #print("next x is for function {} and has coordinates {}".format(next.function_idx, next.x))
        
        if (next.function_idx == 0):
            a = next.x[0]
            b = next.x[1]
            next.set(F(a,b))
        else:
            x = next.x[0]
            next.set(G(x))

    [x,y,function_idx] = opt.get_best_function_eval()

    #print("\nbest function was {}, with y of {}, and x of {}".format(function_idx,y,x))

    assert(abs(y-2) < 1e-7)
    assert(abs(x[0]-5) < 1e-7)
    assert(function_idx==1)



def holder_table(x0,x1):
    return -abs(sin(x0)*cos(x1)*exp(abs(1-sqrt(x0*x0+x1*x1)/pi)))

def test_on_holder_table():
    x,y = find_min_global(holder_table, 
                            [-10,-10],  
                            [10,10],   
                            200)       
    assert (y - -19.2085025679) < 1e-7