Function that plots columns of data on a graph

I have matrix called M with 50 columns and about 5000 rows of data. I'm trying to create a function plotme(M,N) where N is the number of figures to be plotted.

Such that if I have plotme(M,5) 5 figures are created, each containing 10 columns of data. The first figure should plot columns 1-10, the second plots columns 11-20, and so on.

I'd appreciate any help with this. Thanks.

Answer 1

[Star Strider]

Not the full function, but a loop that will do the plotting:

M = randi(100, 100, 50); 

NrFig = 5;
NrPlot = fix(size(M,2)/NrFig);
for k1 = 1:NrFig
    idxrng = [1:NrPlot]+NrPlot*(k1-1)
    figure(k1)
    plot(M(:,idxrng))
end

[Bryan O'Donnell]

Thanks! I've made some headway. As I'm trying to get all 5000 rows of data for each column I'm running the code without the first line so it looks like this:

NrFig = 5; NrPlot = fix(size(M,2)/NrFig); for k1 = 1:NrFig idxrng = [1:NrPlot]+NrPlot*(k1-1) figure(k1) plot(M(:,idxrng)) end

Is there some way the code can be made to produce figures for non-factors of 50, like 9 figures or 11

[Bryan O'Donnell]

I've seen how that works. Thanks. You're a star.

[Bryan O'Donnell]

Quick question: When I try to make a function using the for loop such that

function plotme(M, NrFig)
NrFig = 5;
NrPlot = fix(size(M,2)/NrFig);
for k1 = 1:NrFig
    idxrng = [1:NrPlot]+NrPlot*(k1-1)
    figure(k1)
    plot(M(:,idxrng))
end

I get a 'Not enough input arguments' message. Any ideas what to do from here? Again, Thanks.

[Star Strider]

My pleasure! And thank you for the compliment!

This code for non-factors-of-50 seems to work:

NrFig = 12;
NrPlot = [fix(size(M,2)/NrFig)*ones(1,NrFig-1) size(M,2)-NrFig*fix(size(M,2)/NrFig)];
for k1 = 1:NrFig
    for k2 = 1:length(NrPlot)
        idxrng = [1:NrPlot(k2)]+NrPlot(k2);
        figure(k1)
        plot(M(:,idxrng))
    end
end

I’ve tried it for various values of ‘NrFig’ and it seems to be reliable.

I don’t know where the ‘not enough input arguments’ is being thrown. How are you calling your ‘plotme’ function?

Note that by setting ‘NrFig’ to 5 within the function, you’re overriding whatever value you provide it in the input arguments.

[Bryan O'Donnell]

It does work. Thanks. It's putting it into a function that's an issue for me now. It returns a 'Not enough input arguments' message

[Star Strider]

How are you calling your function? You have to supply it with both arguments, ‘M’ and ‘NrFig’.

Also, note that by setting ‘NrFig’ to 5 within the function, you’re overriding whatever value you provide it in the input arguments.

[Bryan O'Donnell]

I see. How might I define the function so I can put in values of NrFig between 1 and 50?

function plotme(M, NrFig)
NrFig = 12;
NrPlot = [fix(size(M,2)/NrFig)*ones(1,NrFig-1) size(M,2)-NrFig*fix(size(M,2)/NrFig)];
for k1 = 1:NrFig
    for k2 = 1:length(NrPlot)
        idxrng = [1:NrPlot(k2)]+NrPlot(k2);
        figure(k1)
        plot(M(:,idxrng))
    end
end

is what I initially went with- wrongly.

[Bryan O'Donnell]

Sorry I can't find your last comment

[Star Strider]

This is about as robust as I can make my code:

function plotme(M, NrFig)
Incrmnt = round(size(M,2)/NrFig);
NrPlot = [Incrmnt*ones(1,NrFig-1) size(M,2)-(NrFig-1)*Incrmnt];
for k1 = 1:NrFig
        idxrng = [1:NrPlot(k1)]+Incrmnt*(k1-1)
        figure(k1)
        plot(M(:,idxrng))
end

Then call your function as:

M = ...
NrFig = 12;
plotme(M, NrFig)

It will work for ‘NrFig’ values from 1 to 50. I tested it with several, and with 1 and 50 specifically.

[Bryan O'Donnell]

Thanks! This works!

[Star Strider]

My pleasure!