First of all, I would like to say that the GiNaC package is great! I have used it a lot lately! Now, I am trying to solve a linear system, which consists of 18 equations and 18 variables. The matrix and right-hand side do not contain floating point numbers. I have done similar things with smaller matrices and I very much appreciate that GiNaC gives the solution in non-floating point numbers. However, in this concrete case (which is list below). GiNaC is not able to solve the system on my machine with 1 Gb RAM. It runs out of memory! It is of course possible to solve this linear system by using some other library, but it also seems a bit strange that a 18x18 matrix should be that hard to invert. The matrix is non-singular and non of the eigenvalues are "close to 0". The matrix and right-hand side are as follows: Matrix: [ [0,0,0,0,-1/5,0,0,0,0,0,0,0,0,0,-1/30,-1/10,0,0], [0,0,0,0,-1/20,0,0,0,0,0,0,0,0,0,-1/20,-1/15,0,0], [0,0,0,0,-1/30,0,0,0,0,0,0,0,0,0,-1/5,-1/10,0,0], [0,0,0,0,0,0,1/30,1/5,0,0,0,0,0,1/10,0,0,0,0], [0,0,0,0,0,0,1/20,1/20,0,0,0,0,0,1/15,0,0,0,0], [0,0,0,0,0,0,1/5,1/30,0,0,0,0,0,1/10,0,0,0,0], [1/30*sqrt(2),1/10*sqrt(2),0,0,1/30*sqrt(2),0,0,1/5*sqrt(2),1/10*sqrt(2),0,1/5*sqrt(2),1/30*sqrt(2),0,0,0,0,1/10*sqrt(2),1/5*sqrt(2)], [1/20*sqrt(2),1/15*sqrt(2),0,0,1/20*sqrt(2),0,0,1/20*sqrt(2),1/15*sqrt(2),0,1/20*sqrt(2),1/20*sqrt(2),0,0,0,0,1/15*sqrt(2),1/20*sqrt(2)], [1/5*sqrt(2),1/10*sqrt(2),0,0,1/5*sqrt(2),0,0,1/30*sqrt(2),1/10*sqrt(2),0,1/30*sqrt(2),1/5*sqrt(2),0,0,0,0,1/10*sqrt(2),1/30*sqrt(2)], [1/60,1/30,0,1/360,0,1/180,1/60,1/20,0,1/180,0,1/120,1/60,1/30,0,0,1/90,1/120], [1/20,1/30,0,1/180,0,1/60,1/60,1/60,0,1/180,0,1/30,1/30,1/60,0,0,1/60,1/180], [1/60,1/60,0,1/120,0,1/90,1/20,1/60,0,1/180,0,1/120,1/30,1/30,0,0,1/180,1/360], [0,0,1/30,1/180,1/60,1/180,0,0,1/30,1/60,1/20,1/180,0,0,1/60,1/60,1/60,1/30], [0,0,1/60,1/360,1/20,1/180,0,0,1/30,1/180,1/60,1/120,0,0,1/60,1/30,1/90,1/120], [0,0,1/30,1/120,1/60,1/180,0,0,1/60,1/90,1/60,1/360,0,0,1/20,1/30,1/180,1/120], [0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0], [0,0,0,-2,0,0,0,0,0,2,0,0,0,0,0,0,0,0], [0,0,0,-2,0,2,0,0,0,0,0,0,0,0,0,0,0,0]] rhs: [[1],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0],[0]] Kent-Andre Mardal Simula Research Laboratory