| 1234567891011121314151617181920212223242526272829303132333435363738394041424344 |
- function idx = findClosestCentroids(X, centroids)
- %FINDCLOSESTCENTROIDS computes the centroid memberships for every example
- % idx = FINDCLOSESTCENTROIDS (X, centroids) returns the closest centroids
- % in idx for a dataset X where each row is a single example. idx = m x 1
- % vector of centroid assignments (i.e. each entry in range [1..K])
- %
- % Set K
- K = size(centroids, 1);
- % You need to return the following variables correctly.
- idx = zeros(size(X,1), 1);
- % ====================== YOUR CODE HERE ======================
- % Instructions: Go over every example, find its closest centroid, and store
- % the index inside idx at the appropriate location.
- % Concretely, idx(i) should contain the index of the centroid
- % closest to example i. Hence, it should be a value in the
- % range 1..K
- %
- % Note: You can use a for-loop over the examples to compute this.
- %
- m = rows(X);
- for i = 1:m % for each example
- min_xi = zeros(K,1);
- for j = 1:K
- cj = centroids(j,:); % extract the centroid at ith row
- % distance = sqrt(u1-v1)^2 + (u2-v2)^)
- % http://mathonline.wikidot.com/the-distance-between-two-vectors
- min_xi(j) = sum((X(i,:) - cj) .^ 2) ^(1/2);
-
- endfor
- %min_xi;
- [v, idx(i)] = min(min_xi);
- endfor
- % =============================================================
- end
|
