I am currently looking at Math::Matrix, but might end up using PDL.

@dec: yes, all equations are a set of linear equations and yes, they need to be solved simultaneously. Rewriting is not an option, though...

Math::Matrix looks good but I will have to make hundreds or maybe even thousands of runs and am not quite sure yet whether perl would be fast enough for that.

I think I might just try math::matrix first as it seems easier to use quickly and then see if I need more speed ;)

@ambrus: yes, of course that would be an option but I am not that good at numerical problem solving, so I am glad to use code already written and probably optimized to a point where I might not get...

@all: sry for horrible format and thx for all your answers!