#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Task for EggHolder Function
=============================
"""
import numpy
from orion.benchmark.task.base import BaseTask
[docs]class EggHolder(BaseTask):
"""`EggHolder function <http://infinity77.net/global_optimization/test_functions_nd_E.html#go_benchmark.EggHolder>`_
as benchmark task"""
def __init__(self, max_trials=20, dim=2):
self.dim = dim
super(EggHolder, self).__init__(max_trials=max_trials, dim=dim)
[docs] def call(self, x):
"""Evaluate a n-D eggholder function."""
x = numpy.asarray(x)
a = numpy.square(numpy.absolute(x[:-1] - x[1:] - 47))
b = numpy.square(numpy.absolute(0.5 * x[:-1] + x[1:] + 47))
summands = -x[:-1] * numpy.sin(a) - (x[1:] + 47) * numpy.sin(b)
y = numpy.sum(summands)
return [dict(name="eggholder", type="objective", value=y)]
[docs] def get_search_space(self):
"""Return the search space for the task objective function"""
rspace = {"x": "uniform(-512, 512, shape={})".format(self.dim)}
return rspace