Anomaly in mpn_sqrtrem and mpn_rottrem

[Torbjörn Granlund]

nisse at lysator.liu.se (Niels Möller) writes:

  As far as I see, a plain Newton iteration on won't produce an x' inverse
  with 4n bits of accuracy. One would need aither two iterations, or some
  other trick, maybe mixing in some interpolation of x' - x.
  
I don't think one should struggle in order to get n -> 2n bits in a
Newtonian iteration.  It is enough to achieve n -> 2n-k for some
constant k.


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Torbjörn
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