why can't I assign value to a matrix in a loop?

tout = [0,2]; %%%output times

u0 = [30;1;30]; %%%initial data

M=zeros(10,3);

N=zeros(9,3);

y=zeros(9,1);

x=zeros(9,1);

for i=1:10

n=2^i;   %%% the number of equal sized steps

tic %%%start timer

[t,u] = oderk4(@chemcon,tout,u0,n); %%%run the solver

t2=toc; %%%stop timer

M(i,:)=u(end,:);

end

oderk4 is a function for solving ode, and the output of oderk4 are a vector t and a matrix u. I want to use the last row of every matrix u, so I let M to represent them. However, M doesn't have value after the loop. The workspace shows M is NaN. What's wrong with it?

Answer 1

[Jan]

If M contains only NaNs after the loop, this is the reply of oderk4. Therefore I suggest to use the debugger to finde out, where insice the ODE solver the NaNs are produced. There is no problem in the shown code.

[smilerukia]

Thanks! I figure it out. It's the problem of the step size that I chose.