id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12559	sqrt for cpp_int_backend behaves incorrect for small argument values	Rüdiger Brünner <rbruenner@…>	John Maddock	"The sqrt function for multiprecision integers does not work for small values.
Using this code:
{{{
checked_int128_t int1;
for (int i = 10; i >= 0; i--)
{
	int1 = i;
	try
	{
		int1 = sqrt(int1);
		std::cout << ""sqrt("" << i << "") = "" << int1 << std::endl;
	}
	catch (std::exception& ex)
	{
		std::cout << ""sqrt("" << i << "") -> "" << typeid(ex).name() << "": "" << ex.what() << std::endl;
	}
}
}}}

I get the following output:
{{{
sqrt(10) = 3
sqrt(9) = 3
sqrt(8) = 2
sqrt(7) = 2
sqrt(6) = 2
sqrt(5) = 2
sqrt(4) = 2
sqrt(3) -> class boost::exception_detail::clone_impl<struct boost::exception_detail::error_info_injector<class std::overflow_error> >: Unable to allocate sufficient storage for the value of the result: value overflows the maximum allowable magnitude.
sqrt(2) -> class boost::exception_detail::clone_impl<struct boost::exception_detail::error_info_injector<class std::overflow_error> >: Unable to allocate sufficient storage for the value of the result: value overflows the maximum allowable magnitude.
sqrt(1) = 0
sqrt(0) = 0
}}}

While sqrt(3) and sqrt(2) are raising an exception, sqrt(1) gives a wrong result."	Bugs	closed	To Be Determined	multiprecision	Boost 1.62.0	Problem	fixed	multiprecision integer sqrt