On Jul 13, 2011, at 2:16 AM, Pierre Cagne wrote:
Hi,
I'm having a weird dynamic failure using Boost.Rational. Using some rationals and doing a calculus, i'm ending with a rational with a negative denominator, and so unusable for comparison (hence the r.den > 0 assertion failure during the execution).
More precisely, here is a piece of code : (with typedef boost::rational
rat) std::cout << xa << " " << ya << " " << xb << " " << yb << " " << xc << " " << yc << " " << xd << " " << yd << std::endl; // determinant rat delta = (xb - xa)*(yc - yd) - (yb - ya)*(xc - xd); std::cout << "Delta : " << delta << std::endl; /* ... some comparisons on delta ...*/ For the following result : 0/1 1/4 1/2 0/1 0/1 0/1 1/1 0/1 Delta : 1/-4 Assertion failed: (r.den > zero), function operator<, file /usr/local/include/boost/rational.hpp, line 388.
How does it come that Boost does not maintain the assertion correct ? I precise that the same code with the type boost::rational<int> does not produce the failure.
Thankfully.
P.S. : i'm new on this mailing-list ; does my message match with the common pattern of this list ? -- Pierre Cagne pierre.cagne@gmail.com
My guess is that you are getting an integer overflow of the underlying integer type.