How to write a for loop code with an undetermined value

I am stuck while writing this code. Could you give any advise? The matrix N might consist of 16 different values at maximum(0-16), depending on the previous codes.

x=-20:5:20;
y=-20:5:20;
z=40:5:80;
[X,Y,Z]=meshgrid(x,y,z)
h=0;
for i=1:1:length(x)
    for j=1:1:length(y)
        for k=1:1:length(z)
            h=h+1
          M(h,:)=[X(i,j,k), Y(i,j,k), Z(i,j,k)];
          % N(h)=a_MATLAB_function([M(h,1); M(h,2); M(h,3) ],[0;0;0]); 
        end
    end
end
N=[12 12 12 12 12 12 12 8 4 4 4 12 12 ]; % Matrix N's size is 1x729 actually.
%                                          Here it is simplified as a shorter row.
NN = unique(N); NN_length=length(NN);
S=[35 50 100 200];
figure; hold on;

 for i=1:1:NN_length
    NNN(i,:)=find(N==NN(i))
    scatter3(M(NNN(i,:),1),M(NNN(i,:),2),M(NNN(i,:),3),S(i))
 end
hold off;

For the first value of i=1, it is fine. But later I receive error. Because while writing the second row of NNN, first row and second row dimension doesn't match. What can I do? Thanks in advance.

Answer 1

[Jan]

Is there a reason to collect NNN in an array?

for i = 1:NN_length
    NNN = (N == NN(i));    % Without FIND: faster logical indexing
    scatter3(M(NNN, 1), M(NNN, 2), M(NNN, 3), S(i))
end

If you do need NNN later on:

NNN = cell(1, NN_length)
for i = 1:NN_length
    NNN{i} = (N == NN(i));    % Without FIND: faster logical indexing
    scatter3(M(NNN{i}, 1), M(NNN{i}, 2), M(NNN{i}, 3), S(i))
end

[ercan duzgun]

@Jan yes you are right. No need to collect NNN in array. Thank you very much for your help. I appericate your help.

[acun67 acu]

@Jan I could not find any way to direct massage you thats why i post my question in this thread.

sometime earlier i was using a "portable" matlab for learning purpose. I did not install it in my system and i needed any licence key. the whole set up i carried in a pen drive in a zip file. I unziped it and used it. however that model had some limitation. I need that type of IDE/ verson now (argent).

can you/ any one help me by providing that version name?

[Walter Roberson]

Is it possible you are thinking of Octave ?

[acun67 acu]

@Walter Roberson thank you for your advice. Once/twise I used octave, I am not very much confident in octave.

presntly I want to read(import) ,write and plot some file . previouly I have done this in matlab thats why searching for this.

[Walter Roberson]

The closest thing to what you describe that I can recall was some cracked versions of MATLAB.

It is true, though, that for some kinds of Standalone Named User (SNU) Licenses it is possible to use Mathworks as the license administrator; in such a case it would be possible to install from a pen drive, but there was no special version for this, and no special IDE.

There is MATLAB Online, matlab.mathworks.com, but it does not require installation.

[acun67 acu]

@Walter Robersonthank you. matlab online is the last option for me right now. But i did not install that version from pendrive. i just copied and pasted it. is there any way i can get that SNU name or crack name?

[Walter Roberson]

The steps to enable a license to use Mathworks itself as the license server are described at https://www.mathworks.com/help/licensingoncloud/matlab-on-the-cloud.html .

This is available for individual licenses -- Educational or Standard (commercial / professional), but not for Home or Student licenses.

If I recall correctly, the people who offered that old cracked software were arrested for software piracy.

[acun67 acu]

thank you for sharing your knowledge.I am not using this installation and will try to solve my problem using Matlab online.

Answer 2

[David Hill]

What are you trying to plot? What is M?

[n,nn,nnn]=unique(N);%;might want to look at the outputs here, they might help you

[ercan duzgun]

@David Hill , Sorry I forgot about M. Now I edited the codes. M is meshgrid and locations of points in 3D.