Usage example for RK_stab_fun Boundary of stability domain of the original Runge-Kutta method
0001 % Usage example for RK_stab_fun 0002 % Boundary of stability domain of the original Runge-Kutta method 0003 0004 b = [1/6; 1/3; 1/3; 1/6]; 0005 c = [0; 1/2; 1/2; 1]; 0006 A = [0 0 0 0; 0007 1/2 0 0 0; 0008 0 1/2 0 0; 0009 0 0 1 0]; 0010 [ R ] = RK_stab_fun( b,c,A ) 0011 [X,Y] = meshgrid(-3:0.1:0.5,-3.5:0.1:3.5); 0012 Z = X+1i*Y; 0013 Rmod = abs(R); 0014 Rmod = matlabFunction(Rmod); 0015 boundary = feval(Rmod,Z); 0016 contour(X,Y,boundary,[1 1]); 0017 grid on; 0018 title(['original Runge-Kutta method']);