[ublas] Product of scalar and diagonal matrix of integers compile error

Subject: [ublas] Product of scalar and diagonal matrix of integers compile error
From: George Slavov (gpslavov_at_[hidden])
Date: 2012-10-22 11:53:16

I have stumbled into something of a bug. I am using MSVC 2010 and boost
1.51.0. When compiling my code I get an error because internally a call is
made to square root with an integer argument which has no appropriate
overload. Here's a minimal example

#include <iostream>
#include <boost/numeric/ublas/matrix.hpp>
#include <boost/numeric/ublas/banded.hpp>
#include <boost/numeric/ublas/matrix_expression.hpp>
#include <boost/numeric/ublas/io.hpp>

int main()
{
    namespace ublas = boost::numeric::ublas;

    ublas::scalar_matrix<int> A(5,5,1);
    ublas::vector<int> v(5, 0);
    v(0) = 0;
    v(1) = 1;
    v(2) = 2;
    v(3) = 3;
    v(4) = 4;
    ublas::diagonal_matrix<int> D(v.size(), v.data());
    std::cout << A << std::endl;
    std::cout << D << std::endl;

    ublas::matrix<int> result = ublas::prod(A,D);
    std::cout << result << std::endl;
}

It's worth noting that this only fails in a debug build. Defining NDEBUG
causes this problem to go away. I'm guessing some sort of dimension
checking is done internally and the square root function is templated
according to the matrices' value types, but in my case that's an int.
What's an appropriate workaround?

Regards,
George