joint pdf calculation and plot

Question

Yusuf 2015-9-10

0
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https://ww2.mathworks.cn/matlabcentral/answers/241962-joint-pdf-calculation-and-plot

Hi guys,

Having a bit of trouble trying to make a file that calculates and plot the join pdf of 2 variables using 100 bins.

Current attempt which I'm not sure is the best way to go about it

x = A.data(1:57199,2); %gather x data y = A.data(1:57199,3); %gather y data

x_axis = 1:100:57199; % Define edges of bins for x axis. Column vector y_axis = 1:100:57199; % Same for y axis

% Compute corners of 2D-bins: [x_mesh_upper,y_mesh_upper] = meshgrid(x_axis(2:end),y_axis(2:end)); [x_mesh_lower,y_mesh_lower] = meshgrid(x_axis(1:end-1),y_axis(1:end-1));

% Compute centers of 1D-bins: x_centers = (x_axis(2:end)+x_axis(1:end-1))/2; y_centers = (y_axis(2:end)+y_axis(1:end-1))/2;

% Compute pdf: pdf = mean( bsxfun(@le, x(:), x_mesh_upper(:).') ... & bsxfun(@gt, X(:), x_mesh_lower(:).') ... & bsxfun(@le, Y(:), y_mesh_upper(:).') ... & bsxfun(@gt, Y(:), y_mesh_lower(:).') ); pdf = reshape(pdf,length(x_axis)-1,length(y_axis)-1); % pdf values at the % grid points defined by x_centers, y_centers pdf = pdf ./ (y_mesh_upper-y_mesh_lower) ./ (x_mesh_upper-x_mesh_lower); % normalize pdf to unit integral

% Plot pdf figure imagesc(x_centers,y_centers,pdf) axis xy axis equal colorbar title 'pdf'

Thanks in advance guys!