Compute centroid means (unvectorized)
This commit is contained in:
parent
f8c0087ff3
commit
39b09f144a
1 changed files with 17 additions and 8 deletions
|
@ -1,7 +1,7 @@
|
|||
function centroids = computeCentroids(X, idx, K)
|
||||
%COMPUTECENTROIDS returs the new centroids by computing the means of the
|
||||
%COMPUTECENTROIDS returs the new centroids by computing the means of the
|
||||
%data points assigned to each centroid.
|
||||
% centroids = COMPUTECENTROIDS(X, idx, K) returns the new centroids by
|
||||
% centroids = COMPUTECENTROIDS(X, idx, K) returns the new centroids by
|
||||
% computing the means of the data points assigned to each centroid. It is
|
||||
% given a dataset X where each row is a single data point, a vector
|
||||
% idx of centroid assignments (i.e. each entry in range [1..K]) for each
|
||||
|
@ -19,18 +19,27 @@ centroids = zeros(K, n);
|
|||
|
||||
% ====================== YOUR CODE HERE ======================
|
||||
% Instructions: Go over every centroid and compute mean of all points that
|
||||
% belong to it. Concretely, the row vector centroids(i, :)
|
||||
% belong to it. Concretely, the row vector centroids(k, :)
|
||||
% should contain the mean of the data points assigned to
|
||||
% centroid i.
|
||||
% centroid k.
|
||||
%
|
||||
% Note: You can use a for-loop over the centroids to compute this.
|
||||
%
|
||||
|
||||
for k = 1:K
|
||||
count = 0;
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
% XXX vectorize
|
||||
for i = 1:m
|
||||
if idx(i) == k
|
||||
centroids(k, :) += X(i, :);
|
||||
count += 1;
|
||||
end
|
||||
end
|
||||
if count > 0
|
||||
centroids(k, :) /= count;
|
||||
end
|
||||
end
|
||||
|
||||
|
||||
% =============================================================
|
||||
|
|
Reference in a new issue