[issue41458] Avoid overflow/underflow in math.prod()

[Raymond Hettinger]

Raymond Hettinger <raymond.hettin...@gmail.com> added the comment:

Here's a pairwise variant:

    def prod(seq):
        stack = []
        exp = 0
        for i, x in enumerate(seq, start=1):
            m, e = frexp(x)
            exp += e
            stack += [m]
            while not i&1:
                i >>= 1
                x, y = stack[-2:]
                stack[-2:] = [x * y]
        total = 1.0
        while stack:
            total *= stack.pop()
        return ldexp(total, exp)

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<https://bugs.python.org/issue41458>
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