how to create a histogram for featim?

hi matlab community, is something wrong with my coding below? i want to create a histogram for featim. thnkyou so much.

feat=zeros(982,40);
for k=1:982
    A=FYPdatabase{k,1};
    featim=gmlog(A);
    FYPdatabase{k,5}=featim;
end
hist3(featim);

Answer 1

[AKennedy]

Here are some points to consider:

1. Variable Scope: featim is being overwritten in each iteration of the loop. If you want to create a histogram of featim after the loop, you should accumulate the data across iterations.
2. Data Dimensionality: hist3 is used for 2D histograms. If featim is a 1D array, you should use histogram instead (https://www.mathworks.com/help/matlab/ref/matlab.graphics.chart.primitive.histogram.html) .
3. Data Storage: Ensure that gmlog(A) returns data in a format suitable for a histogram (e.g., a 1D array).

feat = zeros(982, 40); % Assuming 40 is the length of feature vector
allFeatim = []; % To accumulate all featim data

for k = 1:982
    A = FYPdatabase{k, 1};
    featim = gmlog(A);
    FYPdatabase{k, 5} = featim;
    
    % Assuming featim is a vector, accumulate it
    allFeatim = [allFeatim; featim(:)]; % Concatenate featim into a single column
end

% Create a histogram for all accumulated featim data
histogram(allFeatim);
xlabel('Feature Value');
ylabel('Frequency');
title('Histogram of Feature Values');

allFeatim = [allFeatim; featim(:)] ensures that all feature values are stored in a single column vector, suitable for histogram plotting. Adjust the code further based on the specific output format of gmlog(A).