I am trying to solve second order ODE equation:
Mx'' = -Kx (where M and K are mass and stiffness matrices that are 300 x 300)
X0 = [x0; xdot0]; (each x0 and xdot0 are 300 x 1 vector) (X0: 600 x 1 vector)
f = @(t, x) String(t, x, M, K, N);
function dydt = String(t, X, M, K, N)
x1 = X(1:N);
x2 = X(N+1:end);
dydt1 = x2;
dydt2 = M \ (-K*x1)
dydt = [dydt1
tSpan = linspace(0 100, 1000)
[~,X] = ode45(f, tSpan, X0);
Issue that I am facing is I am not sure why rows of X are filled with the initial condition X0.
Given function String and using ode45 method, shouldn't it solve the ode and fill the rows with the soltuion accordingly?
Is there any key parts that I am missing?