How to combine multiple arrays and do plotting showing min ave max?

Hi,

I have Variable A (1000x1 cell), and inside that cell is is 1000 samples of numbers (8760x21 double -- screenshot below). How can I generate an 8760x21 matrix on each of the following:

1. Minimum -- min of all the 1000 samples
2. Average -- average of all the 1000 samples
3. Maximum -- max of all the 1000 samples

Further, how to have a plot showing uncertainty in each 21 parameters (columns). By uncertainty, I want to plot in x-axis the number of hours (1 - 8760) and the correponding min ave max of parameter 1 (column 1) on the y-axis, then eventually repeat it for parameter 2 (column 2) so on and so forth. Thank you.

Answer 1

[Ameer Hamza]

Try this code

% generate sample data
A = cell(1,1000);
for i=1:numel(A)
    A{i} = rand(8760, 21);
end

% generate min, max, and average values
M = cat(3, A{:});
result(:,:,1) = max(M, [], 3); % max value
result(:,:,2) = min(M, [], 3); % min value
result(:,:,3) = mean(M, 3); % average value

I guess you want to plot min, max, and average value for each column on a seperate axes. Run the following code to plot the data

figure('WindowState', 'maximized');
ax = axes();
tiledlayout('flow');
for i=1:size(result,2)
    ax = nexttile;
    hold(ax);
    for j=1:size(result,3)
        plot(result(:,i,j));
    end
    title(sprintf('Colums: %d', i))
    xlabel('days');
    ylabel('values');
    legend({'max', 'min', 'average'});
end

[Phoenix]

Hi Ameer,

Thank you for your comment. Few points:

• For the code above, I can't see 'result' and 'M' in the workspace. I'm getting this error: Cannot display summaries of variables with more than 524288 elements. I guess this is Matlab limitation, so that should be fine.

• For the plot, I'm getting this error: Undefined function or variable 'tiledlayout'. I guess it's because I'm using 2018b version and not the latest versions. But apart from that, I'm actually thinking of plotting them (the first 5 columns and the next 5 and the next...) into one axis. One column looks like the one below except the x-axis is from 1 - 8760.

Thanks so much for your help Ameer.

[Phoenix]

Sorry, to be specific, what if I want to plot only specific columns into one axis say for example 7,9,12,18,20? Can you help me come up with a code robust enough to do that given the situation I described earlier? Thanks so much for your help.

[Phoenix]

And I'm assuming the plot will be messy, maybe just the 1 - 2000 (hours) in x-axis instead of the full 1 - 8760 hours? Thanks again.

[Ameer Hamza]

Try this to plot the graph as you have shown in the comment

%%
figure();
ax = axes();
hold on;

cols = [7,9,12,18,20];

for i=1:numel(cols)
    col_data = squeeze(result(:,cols(i),:));
    plot(col_data(:,3),'b');
    X = [1:size(result, 1) size(result, 1):-1:1];
    Y = [col_data(:,2).' flip(col_data(:,1)).'];
    p = patch(X, Y, 'r');
    p.FaceAlpha = 0.2;
    p.EdgeColor = 'none';
end

This shows the general template to make such a plot. You can adapt it according to your requirement. The following was made using random data, so all patches overlap.

[Phoenix]

I will try that. Also, is there a way on how to specify the number of rows/specific range (as what you did with cols)? Say for example, 1 - 2000 instead of full 1 - 8760. Can you show me how would it affect the code in your plotting? Thanks so much for your help.

[Ameer Hamza]

Following code also specifies the range of x-values

figure();
ax = axes();
hold on;

cols = [7,9,12,18,20];

for i=1:numel(cols)
    col_data = squeeze(result(1:2000,cols(i),:)); % <=== range of x-values.
    plot(col_data(:,3),'b');
    X = [1:size(col_data, 1) size(col_data, 1):-1:1];
    Y = [col_data(:,2).' flip(col_data(:,1)).'];
    p = patch(X, Y, 'r');
    p.FaceAlpha = 0.2;
    p.EdgeColor = 'none';
end

[Phoenix]

Sorry, hopefully this is my last request. I'm having trouble to automatically adjust the shade color (min/lower bound and max/upper bound) and the average whenever I'm changing the number of columns which is the parameter to plot in the y-axis. I'm specifically trying to plot cols = [1,2,3,5] in the primary axis, and col = 4 in the secondary axis (yyaxis right???). I need to have specific colors for each of them to distinuish properly each parameter. Lastly, I have been googling on how to put legends which is a line for the average and a shade of color (???) for the uncertainty, but no luck in finding the answer. Thanks very very much for your help, Ameer.

[Phoenix]

Oh, I was able to do it. But my code was a bit 'manual' so it went super long whenever I add new col. Now working on adding the secondary axis. Thanks for your help, Ameer.

[Ameer Hamza]

Is the problem solved? Can you show what you have tried and how you wan to improve it?