Why does my function graph look like a net? How to improve it?

Hi, I tried to plot a vector t against ft, a well-defined function. However after entering the following codes:

figure;plot(t,ft);xlabel('t');ylabel('ft');

I got the following graph, which looks wierd. As for each value t there should be only one value for ft. How could I improve the graph? I attached my data too. Any comments or suggestions are welcome. Thanks!

[Tmat]

Thanks, Stephan. This solved my problem. I thought the t data was constructed monotone.

Answer 1

[Stephen23]

"As for each value t there should be only one value for ft."

Each vector contains exactly 1681 elements, so that is true. But the t values are not monotonic increasing:

>> issorted(t)
ans = 0
>> nnz(find(diff(t)<=0))
ans =  40

and MATLAB plots the data in exactly the t-order that you tell it to, as one long zig-zag line. So far everything is working as documented and as expected.

However it appears that the time data repeats block of 41 elements, which I assume is the same for the data vector. If you expect each of those blocks of data to be displayed as a separate line, then the simplest way is to reshape the data into matrices:

>> Mft = reshape(ft,41,41);
>> Mt  = reshape(t, 41,41);
>> plot(Mt,Mft)

Giving

[Tmat]

Thanks, Stephen.