Re: Comparing boost::multiprecision cpp_int and mpz_int

From: John Maddock (jz.maddock_at_[hidden])
Date: 2019-11-05 08:35:10

On 05/11/2019 07:47, Andy via Boost-users wrote:
> cpp_int is more convenient but mpz_int is faster especially for long 
> numbers?

Probably quite a slower for small numbers, and a lot faster for large ones.

> What say benchmarks?

Out of date, but these may give some clue: 
https://www.boost.org/doc/libs/1_71_0/libs/multiprecision/doc/html/boost_multiprecision/perf/int_real_world.html

> For mpz_int I must install GMP on Linux or build MPIR on WIndows 
> (build lib_mpir_core2) ?
Yes.
> I want make sample benchmark test but I can't convert cpp_it to 
> mpz_int nor iport bits, whereas for cpp_int I can import_bits(x, 
> xBytes.begin(), xBytes.end()) where vector<uint8_t> xBytes;
> Question: is possible import byte array to mpz_int?

No, but the 2 types are explicitly convertible to each other, ie this works:

 Â Â  cpp_int i(2);
 Â Â  mpz_int j(i);
 Â Â  i = cpp_int(j);

John.

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