Source code for example_simulator_functions.goldstein_price

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"""Goldstein-Price function."""

import numpy as np




def goldstein_price(x1: float, x2: float) -> float:
    """Goldstein-Price function.

    Args:
        x1 (float): Input parameter [-2.0, 2.0]
        x2 (float): Input parameter [-2.0, 2.0]

    Returns:
        float: Value of the Goldstein-Price function
    """
    factor_1 = 1.0 + np.square(x1 + x2 + 1.0) * (
        19.0 - 14.0 * x1 + 3.0 * np.square(x1) - 14.0 * x2 + 6.0 * x1 * x2 + 3.0 * np.square(x2)
    )

    factor_2 = 30.0 + np.square(2.0 * x1 - 3.0 * x2) * (
        18.0 - 32.0 * x1 + 12.0 * np.square(x1) + 48.0 * x2 - 36.0 * x1 * x2 + 27.0 * np.square(x2)
    )

    return float(factor_1 * factor_2)