Hi @秀和 髙橋
In MATLAB's ‘TreeBagger’, the out-of-bag (OOB) observations are automatically used for internal validation.
Here is how you can do adjust your code:
mdl = TreeBagger(NumTrees, X, Y, 'OOBPrediction', 'On');
If you want to explicitly retrieve the indices or data of the out-of-bag samples for each tree, you can use the ‘OOBIndices’ property of the ‘TreeBagger’ object like below:
To retrieve the indices:
oobIndices = mdl.OOBIndices; % Please note this property is is not available is R2021b, please upgrade MATLAB to leverage this
To retrieve the data:
treeIndex = 1; % Specify the tree number for which you want the OOB data
oobDataX = X(oobIndices(:, treeIndex), :);
oobDataY = Y(oobIndices(:, treeIndex), :);
Please refer to the input arguments and properties section of this link: www.mathworks.com/help/stats/treebagger.html
Hope this helps!