I've been trying to solve the Deuteron Tensor polarisation equations on the PC, in Python, using a fourth-order Runge-Kutta method. I have a couple of questions: 1) Is Python ok for this job, in that does it give the right answers? The speed is not an issue, it's fast enough for me (I use Numpy and psyco). 2) (which is much more important) How do I cancel out the solutions that "blow up" at infinity? When the computer solves the equations, it gives the most general solution, and doesn't care that the solution blows up at infinity. I DO care ;) , and would like to only get the solution which doesn't blow up... and that would give me th right answer... how do I do it?