Question

我在这个小函数中工作，为随机森林火车准备索引。使用此函数，我获得了一组示例的索引和示例的一部分功能的索引。我发现代码有点慢，有更好更快的方法吗？

这是我的代码

    function [idx_linhas, idx_features ] = prepararsementes(X,features,nseeds,treesize)
    %Esta função prepara os index para a "semeadura" de uma random forest
    idx_linhas = nan(nseeds,treesize);
    idx_features= nan(nseeds,features);

    for idx=1:nseeds
    [~,idx_linhas(idx,:)] = datasample(X,treesize,'Replace',true);
    end


    for idx=1:nseeds
    [~,idx_features(idx,:)] = datasample(X,features,2);
    end

    idx_linhas = idx_linhas.';

    end

提前致谢！

Answer 1

试试这个：

function [idx_linhas, idx_features] = prepararsementes(X, features, nseeds, treesize)

    % instead of loop, call datasample() only once, and reshape
    % note that ('replace', true) is the default, so I omitted that

    [~,idx]      = datasample(X, nseeds*treesize);
    idx_linhas   = reshape(idx, nseeds, treesize).';  

    [~,idx]      = datasample(X, nseeds*features, 2);
    idx_features = reshape(idx, nseeds, features);

end

从统计学的角度来说，我认为结果应该是相同的，因为你没有具体的权重，你在两种情况下都用替换。

随机森林生长

1 个答案: