Beispiel - SAM - ETH Zürich

8 tg = h*(0:N);
9
0 % Plotting of trajectories in phase space
1 f i g u r e(’name’,’pendeul’);
2 ph = p l o t(s(:,1),s(:,2),’g--’,...
3 y_expl(1,:),y_expl(2,:),’r-+’,...
4 y_imp(1,:),y_imp(2,:),’b-+’,...
5 y_mid(1,:),y_mid(2,:),’m-*’); hold on;
6 set(ph(1),’linewidth’,2);
7 ax = axis;
8 p l o t([ax(1) ax(2)],[0 0],’k-’);
9 p l o t([0 0],[ax(3) ax(4)],’k-’);
0 x l a b e l(’{\bf \alpha}’,’fontsize’,14);
1 y l a b e l(’{\bf p}’,’fontsize’,14);
2 legend(’exact solution’,’explicit Euler’,’implicit Euler’,...
3 ’implicit midpoint’,’location’,’southwest’);
4 t i t l e( s p r i n t f(’%d timesteps on [0,%f]’,N,T));
5
6 i f (nargin > 3)
7 p r i n t(’-depsc2’, s p r i n t f(’%s.eps’,filename));
8 end
9
0 % Tracking energies for explicit Euler
Numerische
Mathemtik
R. Hiptmair
rev 35327,
25. April
2011
1.4
p. 92