新建 文本文档.txt

数值积分方法类型Model,1=欧拉法,2=二阶龙格库塔,4=四阶龙格库塔

x[0]={0.4,0,0}
h=500

figure(1);

plot(a(:,1),a(:,2));grid on;
xlabel('time/s');
ylabel('Response'); 
legend('欧拉法');
title('步距h=0.0001');


figure(2);

plot(b(:,1),b(:,2));grid on;
xlabel('time/s');
ylabel('Response'); 
legend('二阶龙格库塔');
title('步距h=0.005');

figure(3)

plot(c(:,1),c(:,2));grid on;
xlabel('time/s');
ylabel('Response'); 
legend('四阶龙格库塔');
title('步距h=0.05');



figure(4)
plot(a(:,1),(a(:,2)-1)*100/1,'-r',b(:,1),(b(:,2)-1)*100/1,'.b',c(:,1),(c(:,2)-1)*100/1,'-+g');grid on;
xlabel('time/s');
ylabel('err%'); 
legend('欧拉偏差','二阶龙格库塔偏差','四阶龙格库塔偏差');
title('数值积分误差分析图')；



figure(4)
plot(a(:,1),(a(:,2)-1)*100/1,'-r',b(:,1),(b(:,2)-1)*100/1,'.b');grid on;
xlabel('time/s');
ylabel('err%'); 
legend('二阶龙格库塔偏差','四阶龙格库塔偏差');
title('数值积分误差分析图')；