Function make_product

modAL/utils/combination.py:37–61

Takes the given functions and makes a function which returns the product of the output of original functions. It works well with functions returning numpy arrays of the same shape. Args: *functions: Base functions for the product. The functions shall have the same argument and

(*functions: Callable, exponents: Optional[Sequence] = None)

def make_product(*functions: Callable, exponents: Optional[Sequence] = None) -> Callable:
    """
    Takes the given functions and makes a function which returns the product of the output of original functions. It
    works well with functions returning numpy arrays of the same shape.

    Args:
        *functions: Base functions for the product. The functions shall have the same argument and if they return numpy
            arrays, the returned arrays shall have the same shape.
        exponents: Exponents of the functions in the product. The i-th given function in the product will be raised to
            the power of exponents[i].

    Returns:
        A function which returns the product function of the given functions output.
    """
    if exponents is None:
        exponents = np.ones(shape=(len(functions)))
    else:
        assert len(functions) == len(exponents), 'the length of exponents must be the ' \
                                                 'same as the number of given functions'

    def product_function(*args, **kwargs):
        return np.prod([functions[i](*args, **kwargs)**exponents[i]
                       for i in range(len(exponents))], axis=0)

    return product_function


def make_query_strategy(utility_measure: Callable, selector: Callable) -> Callable: