GMP used during 3 and a half years to solve MIT's LCS35

[paul zimmermann]

       Dear Marco,

> That's why a few weeks ago on this same list I suggested:
> "What about even sparser exponents? Should we use 2*popcount(n) instead of
> size_in_bits(n) to estimate the best window size? They should be almost
> equivalent on average."
> 
> [ https://gmplib.org/list-archives/gmp-discuss/2019-April/006310.html ]
> 
> If we'd use popcount(n) to choose the "k" for "base-2^k", the
> squaring-only cases like this one would not pre-compute any "a^i".

I support the (clever) idea of using 2*popcount(exponent).
Could you benchmark this against the current version, on
dense and sparse exponents?

Paul