I do not know how to fix this problem (code below)

Question

0 个投票

%ode45_ex.m
%This program solves a system of 3 differential equations
%by using ode45 function 
%y1'=y2*y3*t, y2'=-y1*y3, y3'=-0.51*y1*y2
%y1(0)=0, y2(0)=1.0, y3(0)=1.0
clear; 
clc;
initial=[0.0 1.0 1.0]
tspan=0.0:0.1:10.0;
options=odeset('RelTol', 1.0e-6, 'AbsTol', [1.0e-6 1.0e-6 1.0e-6]);
[t, Y]=ode45(@dydt3, tspan, initial, options);
P=[t Y];
disp(P);
t1=P(:,1);
y1=P(:,2);
y2=P(:,3);
y3=P(:,4);
fid=fopen('output.txt','w');
fprintf(fid,'        t      y(1)         y(2)         y(3)   \n');
fprintf(fid, '------------------------------\n');
for i=1:2:101
fprintf(fid, '  %6.2f    %10.2f   %10.2f    %10.2  \n' t1(i), y1(i), y2(i), y3(i));  %HERE
end
fclose(fid);
plot(t1, Y(:,1), t1, Y(:,2), '-.', t1, Y(:,3), '--'), 
xlabel('t'), ylabel('Y(1), Y(2), Y(3)')
title('Y vs. t');
grid
text(6.0, -1.2, 'y(1)')
text(7.7, -0.25, 'y(2)')
text(4.2, 0.85, 'y(3)');

The program keeps saying that something is wrong with the t1. I bolded where it says the problem is.

Thanks for your help

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Steven Lord 2018-6-7

Please copy and paste the full text of the error message you receive (all the red text) into a comment. Don't paraphrase, post it exactly as it appears in the Command Window.

请先登录，再进行评论。

请先登录，再回答此问题。

Follow Question