how to plot a matrix graph of D(n,m) versus C(n,m) with different colors

I would like to plot a graph of D versus C. For each i have a different color

Answer 1

[Ayush]

Hi @albert Kinda,

You can leverage the "Color" attribute of the "plot" function with a for loop to iterate over each i to plot a graph of D versus C with different colors. You can refer to the following documentation to know more about the "Color" Name-Value argument:

https://www.mathworks.com/help/matlab/ref/plot.html#btzitot-Color

Here is an example code as well for additional reference built-on top of your code:

clc;
clear all;
close all;

C = zeros(12, 49);
D = zeros(12, 49);

for i = 1:12
    for j = 1:49
        C(i, j) = i * j;
        D(i, j) = i - j;
    end
end

% Define colors for each 'i'
colors = lines(12); % Using the 'lines' colormap for 12 different colors

% Plot D versus C with different colors for each 'i'
figure;
hold on;
for i = 1:12
    plot(D(i, :), C(i, :), 'Color', colors(i, :), 'DisplayName', ['i = ' num2str(i)]);
end
hold off;

xlabel('D');
ylabel('C');
title('Plot of D versus C');
legend('show');
grid on;

[albert Kinda]

Thanks but how To change legend with another caracter for exemple alphabétics letters

[Ayush]

You can either change the "DisplayName" name-value argument to iteratively assign alphabetic letters or simply add in the alphabetic letter instead of the parameter "show" in the "legend" function like this:

legend('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L');

[albert Kinda]

Thanks for help

[albert Kinda]

Hi, how to have different markers for each i in order to differentiate them?

Answer 2

[Shantanu Dixit]

Hi Albert,

It is my understanding that you want to plot the two matrix values against each other and have different colors corresponding to each row in the plots.

You can use ‘plot(X,Y,LineSpec)’ from ‘plot’ functionality in MATLAB.

plot(X,Y,LineSpec) creates the plot using the specified line style, marker, and color.

X cand Y point to the corresponding rows from D and C respectively. Colors can be defined using ‘colormap’ as a 12X3 matrix and be passed as LineSpec to the ‘plot’ function.

Additionally, you can refer to the following MathWorks documentation link for better understanding on plotting and colormap:

1. https://www.mathworks.com/help/matlab/ref/plot.html
2. https://www.mathworks.com/help/matlab/ref/colormap.html

[albert Kinda]

Thanks for help and suggestions

Answer 3

[Rahul]

Hi @albert Kinda

I was able to use the code you provided to obtain the plot figure. The following changes can help you get the desired plot:

• Firstly, I defined a colormap using the 'lines' function.
• Further, I made the use of 'hold on' and 'hold off' in the loop while plotting to obtain all points in the same plot.

colors = lines(12);

hold on;

for i=1:1:12
    for j=1:1:49
        plot(D(i,j), C(i,j), '.', 'Color', colors(i, :)); % Use different color for each i
    end
end

hold off;

You can refer to this link for more information regarding 'hold' function: https://www.mathworks.com/help/releases/R2024a/matlab/ref/hold.html?searchHighlight=hold&s_tid=doc_srchtitle

You can refer to this link to style the plot according to your needs: https://www.mathworks.com/help/releases/R2024a/matlab/ref/plot.html?searchHighlight=plot&s_tid=doc_srchtitle

Hope this helps!

[albert Kinda]

Thanks you very much