Convergence Error when Solving System of Matrix Dear forum, Basically, I am trying to analyse the forced vibration of a single span Timoshenko beam on elastic supports at both ends. I want to at the end determine the displacement w(f), rotation phi(f), shear force Q(f) and bending moment (f) at the ends of the beam due to a force excitation on one end of the beam. I want a plot of these paramaters over the excitation frequency f = 1Hz., 2Hz, 3 Hz....1000Hz. To obtain these parameters, I need to solve for a matrix system which looks like this: A.c = b. A is a 4x4 matrix for each frequency, c is a 4x1 vector for each frequency and b is a 4x1 vector for each frequency. So, based on my frequency spacing of 1Hz from 1Hz to 1000Hz, I have 1000 4x4 A matrices in the A(f) matrix, 1000 4x1 matrices in the c(f) vector and 1000 4x1 matrices in the b(f) vector. I have tried using lsolve to solve the system of equation for the c(f) vector but I keep on having an error message which says that the calculation does not converge