test_opt.py 文件源码

def test_log_add():
    m = theano.config.mode
    if m == 'FAST_COMPILE':
        m = 'FAST_RUN'
    m = compile.mode.get_mode(m)
    m = m.excluding('fusion')
    m = copy.copy(m)
    # No need to put them back as we have a new object
    m.check_isfinite = False

    # check some basic cases
    x = dvector()
    y = dvector()
    f = function([x, y], T.log(T.exp(x) + T.exp(y)), mode=m)

    f([10000], [10000])  # causes overflow if handled incorrectly
    assert numpy.isfinite(f([10000], [10000]))
    utt.assert_allclose(f([10000], [10000]), 10000 + numpy.log1p(1))

    # test that it give the same result when it don't overflow
    f([10], [10])  # don't causes overflow
    utt.assert_allclose(f([10], [10]), 10 + numpy.log1p(1))

    # test that it also works with more than two args, (this currently fails)
    x = dvector()
    y = dvector()
    f = function([x, y], T.log(T.exp(x) + T.exp(y) + T.exp(x - y) + T.exp(
        x + y)), mode=m)

    try:
        f([10000], [10000])  # causes overflow if handled incorrectly
        utt.assert_allclose(f([10000], [10000]), 20000)
    except utt.WrongValue:
        raise SkipTest("log(add(exp)) is not stabilized when adding "
                       "more than 2 elements, see #623")

    # TODO: test that the optimization works in the presence of broadcasting.

    # TODO: (write and) test that the optimization works with Sum in addition to working with Add.