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Author serhiy.storchaka
Recipients mark.dickinson, martin.panter, ned.deily, rhettinger, serhiy.storchaka, steven.daprano, tim.peters, vstinner
Date 2016-08-27.05:03:25
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What if use pow() with exactly represented degree in approximating step?

    def rootn(x, n):
        g = x**(1.0/n)
        m = 1 << (n-1).bit_length()
        if n != m:
            g = (x*g**(m-n))**(1.0/m)
        return g

Maybe it needs several iterations, because it converges slower than Newton approximation. But every step can be faster.
Date User Action Args
2016-08-27 05:03:25serhiy.storchakasetrecipients: + serhiy.storchaka, tim.peters, rhettinger, mark.dickinson, vstinner, ned.deily, steven.daprano, martin.panter
2016-08-27 05:03:25serhiy.storchakasetmessageid: <>
2016-08-27 05:03:25serhiy.storchakalinkissue27761 messages
2016-08-27 05:03:25serhiy.storchakacreate