|
- function centroids = computeCentroids(X, idx, K)
- %COMPUTECENTROIDS returns 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
- % 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
- % example, and K, the number of centroids. You should return a matrix
- % centroids, where each row of centroids is the mean of the data points
- % assigned to it.
- %
-
- % Useful variables
- [m n] = size(X);
-
- % You need to return the following variables correctly.
- 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, :)
- % should contain the mean of the data points assigned to
- % centroid i.
- %
- % Note: You can use a for-loop over the centroids to compute this.
- %
- centroidsSum = zeros(K,1);
- for i = 1 : m
- centroids(idx(i), :) = centroids(idx(i), :) .+ X(i, :);
- centroidsSum(idx(i)) = centroidsSum(idx(i)) + 1;
- end
- for i = 1 : K
- centroids(i,:) = centroids(i,:) ./ centroidsSum(i) ;
- end
-
- % =============================================================
-
-
- end
|
