id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6022	WeightType is misleading in boost::random::discrete_distribution	Tim White <boost.10.wtwhite@…>	No-Maintainer	"The class template `boost::random::discrete_distribution` is parameterized by types `IntType` (defaulting to `int`) and `WeightType` (defaulting to `double`).  Could you please update the documentation to clarify that `WeightType` must be a floating-point type?  Alternatively, if the implementation could be changed to allow integer `WeightType`s that would be even better!  (But I imagine that could be a lot of work.)

A bit more background:

The documentation doesn't give any constraints on `WeightType`, and in fact the documentation for one of the constructors gives as an example

{{{
discrete_distribution<> dist{1, 4, 5};
}}}

which indicates that weights don't have to sum to 1, and hints at the possibility of using an integer `WeightType` -- which would often be convenient and efficient.  However, the following snippet fails compilation:

{{{
#include <boost/random.hpp>
void f() {
    int w[] = {1, 4, 5};
    boost::random::discrete_distribution<int, int> dist(w, w + 3);
}
}}}

Changing the `<int, int>` to `<int, double>` or just `<int>` enables compilation.  (Also, looking at the Boost implementation, I see a call to an internal `normalize()` method that divides all weights by their sum, so it looks like support for integer `WeightType`s was never intended.)

Thanks,
Tim
"	Bugs	closed	To Be Determined	random	Boost 1.47.0	Problem	fixed