Plot 2 matrices in one graph with 3 axis

Hi, I have to plot curves "MSE" witch depend on 2 variables. Variable 1 : "pct=1:1:n" and variable 2 : "CR" .

But "CR" depends on two variables also:

 "ptx=1:1:n" and "pct=1:1:n"
MSE=fct(CR,pct)

Here a simplification of the code:

for pct=1:1:n
  for ptx=1:1:n
     calculate CR(pct,ptx)
     calculate MSE(pct,ptx)
  end
end

I want to plot curves of "MSE" in function with "pct" and "CR" , it means ;

axis x : "pct"
axis y : "CR"
axis z  : "MSE"

That is, a kind of succession of curves Thank you in advance

[Ameer Hamza]

Have you tried plot3()

plot3(pct, CR, MSE);

[kortas manel]

MSE is a matrix of size (n*n)= (pct=1:1:n)*(ptx=1:1:n) CR is a matrix of size (n*n)= (pct=1:1:n)*(ptx=1:1:n)

When I tried : plot3(1:n, CR , MSE) , I obtained this

</matlabcentral/answers/uploaded_files/121689/3d.png> This is not what I expect .

the curves that I want to get comes from this loop

for pct=1:n figure(pct) plot(CR(pct,:),MSE(pct,:)) end

But I want these curves in one graph positioned successively according to pct values

[Ameer Hamza]

Your x variable is an n-element vector, whereas y and z are nxn matrices. And from your for loop example, it seems that you want several 2D plots. Can you show an example plot similar to what you are trying to draw?

[kortas manel]

Yes that's it, but I want them in the same graph so that the first curve containing MSE = fct (CR) put on the plane (y, z) intersects x axis at point pct = 1, the second curve containing MSE = fct (CR) put on the plane (y, z) cross section x at point pct = 2, etc.

Answer 1

[Ameer Hamza]

From your question description, it appears you want something like this

Here is a sample code with random values to generate this

n = 10;
x = 1:n;  % 1 x n vector
y = repmat(1:n, n, 1);  % n x n matrix
z = rand(n);  % n x n matrix

plot3(1*ones(n,1), y(1, :), z(1, :)); % plot one line outside for loop to get the axes handle
ax = gca;
hold(ax);
grid on
xlabel('pct');
ylabel('CR');
zlabel('MSE');

for i=2:n
  plot3(i*ones(n,1), y(i, :), z(i, :));
end

[kortas manel]

That's what I need, thank you , just another point : when x=1:10 but y=repmat(1:9,10,1). It means y of size(10*9) also z is of size(10*9) it gives : Vectors must be the same length. Normally it should not be a problem as vectors y(i,:) and z(i,:) have the same length

[Ameer Hamza]

In that case, you will also need to adjust the first input to plot3()

plot3(i*ones(9,1), y(i, :), z(i, :));

I guess this might be causing the issue.

Answer 2

[Guillaume]

If your calculate functions can operate on matrices:

[pct, ptx] = ndgrid(n);
CR = yourcalculateCRfunction(pct, ptx);
MSE = yourcalculateMSEfunction(pct, ptx);
plot3(pct, CR, MSE);

Otherwise

[pct, ptx] = ndgrid(n);
CR = zeros(size(pct));
MSE = zeros(size(pct));
for i = 1:numel(pct)
   CR(i) = yourcalculateCRfunction(pct(i), ptx(i));
   MSE(i) = yourcalculateMSEfunction(pct(i), ptx(i));
end
plot3(pct, CR, MSE);