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POMahout evaluation - unable to recommend in x cases
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  1. POMahout evaluation - unable to recommend in x cases
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    copied!<p>I am trying to evaluate the recommender algorithms on my data set which probably is sparse, and I have only 341 items for around 20 000 users. I just want to evaluate all of the similarity algorithms. I tried almost all user-based recommendations, and for all of them I am getting this INFO from the evaluator, no matter which one, (<code>AverageAbsoluteDifferenceRecommenderEvaluator</code> or Root mean-square scoring Evaluator) which is <em>Unable to recommend in xXXX cases</em>. However the final output still have some result. Here is the output of my evaluator:</p> <pre><code>3/06/17 14:11:35 INFO eval.AbstractDifferenceRecommenderEvaluator: Beginning evaluation using 0.7 of org.apache.mahout.cf.taste.impl.model.jdbc.PostgreSQLJDBCDataModel@44303e7b 13/06/17 14:15:17 INFO model.GenericDataModel: Processed 10000 users 13/06/17 14:15:17 INFO model.GenericDataModel: Processed 20000 users 13/06/17 14:15:17 INFO model.GenericDataModel: Processed 20530 users 13/06/17 14:15:17 INFO eval.AbstractDifferenceRecommenderEvaluator: Beginning evaluation of 11240 users 13/06/17 14:15:17 INFO eval.AbstractDifferenceRecommenderEvaluator: Starting timing of 11240 tasks in 4 threads 13/06/17 14:15:17 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 4ms 13/06/17 14:15:17 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 57MB / 101MB 13/06/17 14:15:17 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 3 cases 13/06/17 14:15:19 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 4ms 13/06/17 14:15:19 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 48MB / 99MB 13/06/17 14:15:19 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 882 cases 13/06/17 14:15:20 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:20 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 33MB / 109MB 13/06/17 14:15:20 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 1787 cases 13/06/17 14:15:22 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:22 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 41MB / 86MB 13/06/17 14:15:22 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 2687 cases 13/06/17 14:15:23 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:23 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 38MB / 98MB 13/06/17 14:15:23 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 3569 cases 13/06/17 14:15:24 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:24 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 28MB / 93MB 13/06/17 14:15:24 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 4465 cases 13/06/17 14:15:26 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:26 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 41MB / 88MB 13/06/17 14:15:26 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 5420 cases 13/06/17 14:15:27 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:27 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 45MB / 90MB 13/06/17 14:15:27 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 6317 cases 13/06/17 14:15:28 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:28 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 46MB / 103MB 13/06/17 14:15:28 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 7220 cases 13/06/17 14:15:30 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:30 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 72MB / 102MB 13/06/17 14:15:30 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 8145 cases 13/06/17 14:15:31 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:31 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 67MB / 99MB 13/06/17 14:15:31 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 9084 cases 13/06/17 14:15:33 INFO eval.AbstractDifferenceRecommenderEvaluator: Average time per recommendation: 5ms 13/06/17 14:15:33 INFO eval.AbstractDifferenceRecommenderEvaluator: Approximate memory used: 31MB / 83MB 13/06/17 14:15:33 INFO eval.AbstractDifferenceRecommenderEvaluator: Unable to recommend in 9982 cases 13/06/17 14:15:33 INFO eval.AbstractDifferenceRecommenderEvaluator: Evaluation result: 1.643042326271061 </code></pre> <p>I don't understand the numbers, why they show so many times, and is this unable to recommend in xxx cases bigger then 20% of all my data? Does it mean that for one user it can't recommend in 3 cases, and for other in 9892?</p>
 

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