如何根据 Matlab kmean() 函数的输出计算与簇质心的距离
How to calculate distance from cluster centroids from the outputs of Matlab kmean() function
我有 2 个来自 k 均值 matlab 函数的输出簇
[idx,C] = kmeans(X,2);
我不知道如何使用"idx"
计算质心与簇中每个点之间的距离
我想得到所有点到质心的距离 >2
的矩阵
% not Matlab code; just illustrating concept
例子
c1->{x1,x2}=
x1-c1=3
x2-c1=2
c2->{y1,y2}=
y1-c2=4
y2-c2=1
output={y1,x1}
这样试试:
更新答案现在使用循环。
r = randn(300,2)*5;
r(151:end,:) = r(151:end,:) + 15;
n_clusters = 2;
[idx, C] = kmeans(r, n_clusters);
clusters = cell(n_clusters, 1);
distances = cell(n_clusters, 1);
for ii = 1:n_clusters
clusters{ii} = r(idx==ii, :);
distances{ii} = sqrt(sum((clusters{ii}-C(ii,:)).^2,2));
end
figure;
subplot(1,2,1);
for ii = 1:n_clusters
plot(clusters{ii}(:,1), clusters{ii}(:,2), '.');
hold on
plot(C(ii,1), C(ii,2), 'ko','MarkerFaceColor', 'w');
end
title('Clusters and centroids');
subplot(1,2,2);
for ii = 1:n_clusters
plot(clusters{ii}(distances{ii} > 2,1), clusters{ii}(distances{ii} > 2,2), '.');
hold on
plot(C(ii,1), C(ii,2), 'ko','MarkerFaceColor', 'w');
end
title('Centroids and points with distance > 2');
要得到一个点数大于 2 的矩阵的单元格,你可以这样做:
distant_points = cell(n_clusters,1);
for ii = 1:n_clusters
distant_points{ii} = clusters{ii}(distances{ii} > 2,:)
end
我有 2 个来自 k 均值 matlab 函数的输出簇
[idx,C] = kmeans(X,2);
我不知道如何使用"idx"
计算质心与簇中每个点之间的距离我想得到所有点到质心的距离 >2
的矩阵% not Matlab code; just illustrating concept
例子 c1->{x1,x2}= x1-c1=3 x2-c1=2
c2->{y1,y2}=
y1-c2=4
y2-c2=1
output={y1,x1}
这样试试:
更新答案现在使用循环。
r = randn(300,2)*5;
r(151:end,:) = r(151:end,:) + 15;
n_clusters = 2;
[idx, C] = kmeans(r, n_clusters);
clusters = cell(n_clusters, 1);
distances = cell(n_clusters, 1);
for ii = 1:n_clusters
clusters{ii} = r(idx==ii, :);
distances{ii} = sqrt(sum((clusters{ii}-C(ii,:)).^2,2));
end
figure;
subplot(1,2,1);
for ii = 1:n_clusters
plot(clusters{ii}(:,1), clusters{ii}(:,2), '.');
hold on
plot(C(ii,1), C(ii,2), 'ko','MarkerFaceColor', 'w');
end
title('Clusters and centroids');
subplot(1,2,2);
for ii = 1:n_clusters
plot(clusters{ii}(distances{ii} > 2,1), clusters{ii}(distances{ii} > 2,2), '.');
hold on
plot(C(ii,1), C(ii,2), 'ko','MarkerFaceColor', 'w');
end
title('Centroids and points with distance > 2');
要得到一个点数大于 2 的矩阵的单元格,你可以这样做:
distant_points = cell(n_clusters,1);
for ii = 1:n_clusters
distant_points{ii} = clusters{ii}(distances{ii} > 2,:)
end