我的代码运行，有时会出现错误“使用horzcat时出错，所连接的矩阵维数不一致。”

Question

This is my code and I understand you have to have dimensions of matrix equal to line up which is why I transpose y to make it a column and both have 21 rows but sometimes the code runs when I publish but then after one time of running it persistently then hits this error if I try to run it again. It says error on line disp([t,y])

%Define parameters         
A=1250; %m^2        
Q=450; %m^3/d       
a=150;        
y(1)=0;        
t=[0:0.5:10]';          
y=y';          
disp('        t            y')          
disp('----------------------')            
disp([t,y])           
%Set loop in (Eulers method) for the amount of steps we want to do to
%find our estimated solution       
for i=1:20           
y(i+1)=y(i)+((3*(Q/A)*sin(t(i)).^2)-(a*(1+y(i)).^1.5/A))*0.5;             
end             
%generate plot for data           
plot(t,y)          
title('Plot of y vs t')               
xlabel('time')              
ylabel('y')                 

Answer 1

Your problem is that y only has one element when you attempt to display it.

You're constructing [t,y] which is a concatenation of two elements - t and y . But t is a vector of some length (21), whereas you have not initialized y to be anything.

If you really do want to display y before it's been set, you can initialize it to zero using y(1:21) = 0

But why do you want to display y and t before you've calculated your estimated solution, anyway?