0001
0002
0003
0004 b = [1/2; 1/2];
0005 c = [0; 1];
0006 A = [0 0;
0007 1 0];
0008 [ R ] = RK_stab_fun( b,c,A )
0009 [X,Y] = meshgrid(-2.5:0.1:2.5,-2:0.1:2);
0010 Z = X+1i*Y;
0011 Rmod = abs(R);
0012 Rmod = matlabFunction(Rmod);
0013 boundary = feval(Rmod,Z);
0014 contour(X,Y,boundary,[1 1]);
0015 hold on;
0016 a = 1;
0017 c = [0; 2*a];
0018 A = [0 0;
0019 a a];
0020 [ R ] = RK_stab_fun( b,c,A )
0021 Rmod = abs(R);
0022 Rmod = matlabFunction(Rmod);
0023 boundary = feval(Rmod,Z);
0024 contour(X,Y,boundary,[1 1]);
0025 grid on;
0026 title(['Exercise 6.19']);