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I want to classify histograms/distributions using K-Nearest-Neighbor. I can measure distances/dissimilarities between the distributions (using euclidean distance, kullback-leibler divergence...), thus I can obtain distance matrices. I was wondering since Nearest Neighbors measure distances anyway, can I incorporate distance matrices directly into the algorithm?

Also if you know a function in R or python that already exists, I'm interested. thank you

More details on my dataset: I have more than 100 observations that I want to classify in 2 classes (I have the labels) and all the features (4 features) are histograms (1 feature = 1 histogram).

UPDATE:

Using R: function "knn_dist" from "evclust" package

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  • $\begingroup$ Are you looking for something like K-means? $\endgroup$
    – user2974951
    Nov 30, 2018 at 10:34
  • $\begingroup$ Not really, I know that you can use similarity matrix as an input in K-medoid algorithm but since I have class labels I want to use a supervised learning for the classification task (k-means and K-medoids are unsupervised learning but KNN is supervised learning) $\endgroup$
    – learners
    Nov 30, 2018 at 11:39
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    $\begingroup$ Read this thread about k-means stats.stackexchange.com/q/32925/3277. Same is true for other analyses. To embed a distance matrix into feature space by means of MDS with sufficient number of dimensions giving good fit (stress value). Then proceed with knn or k-means etc. as usual. Of course, your matrix cannot be huge, or MDS won't cope. $\endgroup$
    – ttnphns
    Dec 1, 2018 at 9:42
  • $\begingroup$ Thank you @ttnphns .So if I understand well, you can't just use a distance matrix as an input in knn algorithm , you have to do MDS first than use knn like usual ? and second question MDS works only if the distance we use is the euclidean distance? $\endgroup$
    – learners
    Dec 2, 2018 at 18:12
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    $\begingroup$ MDS is for any distance. I recommend you to read something about MDS before using it. $\endgroup$
    – ttnphns
    Dec 3, 2018 at 7:41

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yes, it's possible because KNN finds the nearest neighbor, you already have distance/similarity matrix then the next step is to fix k value and then find the nearest value. Out of all the nearest neighbor take the majority vote and then check which class label it belongs.

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