hi everybody while working in my physics simulator (rigid body ) i was taking a s aguide david baraff amazing tutorials,, whic guided me step by step through the whole process, but when i reched the last problem (and harderst ) i had to solve (rest contact forces) the author assumed that i have a routine called (QP_SOLVE) which is called quadratic programming solver, which takes a N*N matrix and an N vector and returs a N vector of some solutions can any1 tell me where to find that routine..? Flutey Shady El Mously Egyptian Game Programmer (there is no knowledge that is not power)

Use Kramer''s Rule. First, calculate the determinant of the NxN matrix, and call it D. Then, for each unknown Xk, make another NxN matrix but replace the kth column with the N vector and calculate the determinant of that matrix and call it Dk. Then, Xk = Dk / D. Note that if D == 0, then there is no solution.

Aprosenf: Quadratic programming is not the same as solving systems of linear equations. Even if this were the problem, Cramer''s rule is not the preferred solution.

As for QP, I don''t know where you would find a routine that specialized. You can take entire university level classes in linear programming, and that''s a lot simpler. I would recommend looking for papers online that might be able to help.