Weibull does not seem to work gives error"Error using makedist Distribution name 'Weibull' is unrecognized."

c = 8.1; % Scale factor

k = 2.03; % Shape factor

N = 1000; % Number of plot data points

pd = makedist('Weibull','a',c,'b',k) %Selection of Weibull

x = linspace(0,25,N);

y = pdf(pd,x); % Weibull output function

cd = 1 - exp(-(x/c).^k); % Cumulative distribution

yyaxis left

plot(x,100*y, 'k','LineWidth',2)

title({['Weibull and Cumulative Probability Distributions'], ...

['k = ', num2str(k), ' and c = ', num2str(c)]});

xlabel('Wind Velocity (m/s)');

ylabel('Probability (%)', 'Color','k');

hold on

yyaxis right

plot(x,100*cd, 'r','LineWidth',2)

ylabel('Probability (%)');

legend('Weibull', 'Cumulative')

axis([0 25 0 120]);

grid on

grid minor

It gives the following error:

Error using makedist

Distribution name 'Weibull' is unrecognized.

[Ganapathi Subramanian R]

Hi Gihahn,

The above script is working fine for me in MATLAB R2023b. Could you let me know which version of MATLAB you are using?

Additionally, to execute the above code you should have a valid license to access Statistics and Machine Learning Toolbox.

Answer 1

[Jayanti]

Hi Gihahn,

If you want to use Weibull distributions in MATLAB, particularly functions like makedist, pdf you need to have the Statistics and Machine Learning Toolbox installed. Your error suggests that you don’t have the Statistics and Machine Learning Toolbox installed. When I tried running the code without this toolbox, I faced the same issue.

You can also try running the “ver” command to find the product name, version number, and release name for all the Matlab and other installed products.

However, after installing the Statistics and Machine Learning Toolbox the code no longer throws errors.

I hope this helps you!