Beispiel - SAM - ETH Zürich

3 E_pot = -g/l*cos(y(1,:));
4 E_pot = E_pot - min(E_pot) + min(E_kin);
5 E_tot = E_kin + E_pot;
6
7 f i g u r e(’name’,’Pendulum: energy’);
8 p l o t(tg,E_kin,’b-’,...
9 tg,E_pot,’c-’,...
0 tg,E_tot,’r-’);
1 x l a b e l(’{\bf time t}’,’fontsize’,14);
2 y l a b e l(’{\bf energy}’,’fontsize’,14);
3 legend(’kinetic energy’,’potential energy’,’total energy’);
4 t i t l e(’Energies for {\bf implicit} Euler discrete evolution’);
5
6 i f (nargin > 3)
7 p r i n t(’-depsc2’, s p r i n t f(’%s_EnImpl.eps’,filename));
8 end
9
0 % Tracking energies for implicit midpoint rule
1 y = y_mid;
2
3 E_kin = 0.5*(y(2,:).^2);
4 E_pot = -g/l*cos(y(1,:));
5 E_pot = E_pot - min(E_pot) + min(E_kin);
Numerische
Mathemtik
R. Hiptmair
rev 35327,
25. April
2011
1.4
p. 94