예제 #1
0
def ufuncify(args, expr, **kwargs):
    """
    Generates a binary ufunc-like lambda function for numpy arrays

    ``args``
        Either a Symbol or a tuple of symbols. Specifies the argument sequence
        for the ufunc-like function.

    ``expr``
        A SymPy expression that defines the element wise operation

    ``kwargs``
        Optional keyword arguments are forwarded to autowrap().

    The returned function can only act on one array at a time, as only the
    first argument accept arrays as input.

    .. Note:: a *proper* numpy ufunc is required to support broadcasting, type
       casting and more.  The function returned here, may not qualify for
       numpy's definition of a ufunc.  That why we use the term ufunc-like.

    References
    ==========
    [1] http://docs.scipy.org/doc/numpy/reference/ufuncs.html

    Examples
    ========

    >>> from sympy.utilities.autowrap import ufuncify
    >>> from sympy.abc import x, y
    >>> import numpy as np
    >>> f = ufuncify([x, y], y + x**2)
    >>> f([1, 2, 3], 2)
    [ 3.  6.  11.]
    >>> a = f(np.arange(5), 3)
    >>> isinstance(a, np.ndarray)
    True
    >>> print a
    [ 3. 4. 7. 12. 19.]

    """
    y = C.IndexedBase(C.Dummy('y'))
    x = C.IndexedBase(C.Dummy('x'))
    m = C.Dummy('m', integer=True)
    i = C.Dummy('i', integer=True)
    i = C.Idx(i, m)
    l = C.Lambda(args, expr)
    f = implemented_function('f', l)

    if isinstance(args, C.Symbol):
        args = [args]
    else:
        args = list(args)

    # ensure correct order of arguments
    kwargs['args'] = [y, x] + args[1:] + [m]

    # first argument accepts an array
    args[0] = x[i]
    return autowrap(C.Equality(y[i], f(*args)), **kwargs)
예제 #2
0
def ufuncify(args, expr, **kwargs):
    """Generates a binary ufunc-like lambda function for numpy arrays

    ``args``
        Either a Symbol or a tuple of symbols. Specifies the argument sequence
        for the ufunc-like function.

    ``expr``
        A Sympy expression that defines the element wise operation

    ``kwargs``
        Optional keyword arguments are forwarded to autowrap().

    The returned function can only act on one array at a time, as only the
    first argument accept arrays as input.

    .. Note:: a *proper* numpy ufunc is required to support broadcasting, type
       casting and more.  The function returned here, may not qualify for
       numpy's definition of a ufunc.  That why we use the term ufunc-like.

       See http://docs.scipy.org/doc/numpy/reference/ufuncs.html

    :Examples:

    >>> from sympy.utilities.autowrap import ufuncify
    >>> from sympy.abc import x, y, z
    >>> f = ufuncify([x, y], y + x**2)             # doctest: +SKIP
    >>> f([1, 2, 3], 2)                            # doctest: +SKIP
    [2.  5.  10.]

    """
    y = C.IndexedBase(C.Dummy('y'))
    x = C.IndexedBase(C.Dummy('x'))
    m = C.Dummy('m', integer=True)
    i = C.Dummy('i', integer=True)
    i = C.Idx(i, m)
    l = C.Lambda(args, expr)
    f = implemented_function('f', l)

    if isinstance(args, C.Symbol):
        args = [args]
    else:
        args = list(args)

    # first argument accepts an array
    args[0] = x[i]
    return autowrap(C.Equality(y[i], f(*args)), **kwargs)