I need to compute 5^64 with boost multiprecision library which should yield 542101086242752217003726400434970855712890625 but boost::multiprecision::pow() takes mpfloat and gives 542101086242752217003726392492611895881105408.
However If I loop and repeatedly multiply using mpint I get correct result.
Is it a bug ? or I am using boost::multiprecision::pow() in a wrong way ? or I there is an alternative of using boost::multiprecision::pow() ?
#include <iostream>
#include <string>
#include <boost/multiprecision/gmp.hpp>
typedef boost::multiprecision::mpz_int mpint;
typedef boost::multiprecision::number<boost::multiprecision::gmp_float<4> > mpfloat;
int main(){
mpfloat p = boost::multiprecision::pow(mpfloat(5), mpfloat(64));
std::cout << p.template convert_to<mpint>() << std::endl;
mpint res(1);
for(int i = 0; i < 64; ++i){
res = res * 5;
}
std::cout << res << std::endl;
}
