Python math 模块，expm1() 实例源码

def expm1(node): return merge([node], math.expm1)

def test_one():
    from math import sin, cos, tan, asin, acos, atan
    from math import sinh, cosh, tanh, asinh, acosh, atanh
    from math import exp, expm1, log, log10, log1p, sqrt, lgamma
    from math import fabs, ceil, floor, trunc, erf, erfc
    try:
        from math import log2
    except ImportError:
        def log2(x):
            return log(x) / log(2)

    def wrapper(f, v):
        try:
            return f(v)
        except ValueError:
            if f == sqrt:
                return float('nan')
            if v >= 0:
                return float('inf')
            else:
                return -float('inf')

    def compare(a, b):
        if isfinite(a) and isfinite(b):
            return assert_almost_equals(a, b)
        return str(a) == str(b)

    for f in [sin, cos, tan, asin, acos, atan,
              sinh, cosh, tanh, asinh, acosh, atanh,
              exp, expm1, log, log2, log10, log1p, sqrt,
              lgamma,
              fabs, ceil, floor, trunc,
              erf, erfc]:
        for p in [0.5, 1]:
            a = random_lst(p=p)
            b = SparseArray.fromlist(a)
            c = getattr(b, f.__name__)()
            res = [wrapper(f, x) for x in a]
            index = [k for k, v in enumerate(res) if v != 0]
            res = [x for x in res if x != 0]
            print(f, p, c.non_zero, len(res))
            assert c.non_zero == len(res)
            [assert_almost_equals(v, w) for v, w in zip(index,
                                                        c.index)]
            [compare(v, w) for v, w in zip(res,
                                           c.data)]