test_support.py 文件源码

def compose_functions(cls,
                          x,
                          number_of_compositions=1,
                          functions=(np.sin, np.exp, np.square, np.polyval,
                                     np.tan, ),
                          clip_big_values=True,
                          clip_value=1e6):
        """Compose functions from an iterable of functions.

        This is a helper function to cover a more real life scenario of
        plottings.

        Arguments:
            x (numpy.array): array for which composed values will be computed.
            number_of_compositions (int): number of compositions of functions.
            functions (tuple): an iterable of functions.
            clip_big_values (bool): whether or not to limit function extremes.
            clip_value (float): limit values for function composition.

        Returns:
            y (numpy.array): array of composed functions

        """
        i = 0
        y = x
        while i < number_of_compositions:
            func = np.random.choice(functions)
            if func == np.polyval:
                n_coefs = np.random.randint(0, 10)
                coefs = np.random.randint(-50, 50, size=n_coefs)
                y = func(coefs, x)
            else:
                y = func(y)
            if clip_big_values:
                y = np.clip(y, -clip_value, clip_value)
            i += 1
        return y

    # Goes with 'fast' parameters by default.