coursera 吴恩达作业第七次提交

findClosestCentroids.m

m = size(X, 1); % m  
for i = 1:m  
dist = [];  
for j = 1:K  
dist(j) =  sum((X(i, :)-centroids(j, :)) .^ 2);  
end  
[min_dist, min_idx] = min(dist);  
idx(i) = min_idx;  
end

computeCentroids.m

for i = 1:K  
idx_set = find(i == idx);  
ck = numel(idx_set);  
if(0 ~= ck)  
cen_sum = sum(X(idx_set, :));  
centroids(i, :) = cen_sum / ck;  
end   
end 

pca.m

Omega = X' * X / m;  
[U S V] = svd(Omega);

projectData.m

Ureduce = U(:, 1:K);  
x = X';  
Z = x' * Ureduce; % i.e. X * Ureduce

recoverData.m

Ureduce = U(:, 1:K);  
X_rec = Z * Ureduce';