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Martin Illecker updated MAHOUT-1266: ------------------------------------ Description: Hello, I think I have found two minor problems in *DistributedRowMatrix*. In [1] the condition is wrong, because (l x m) * (m x n) = (l x n). The condition should be like in [2]. And in *times*[3] the {{this.transpose()}} seems to be missing? (See [4]) Do you have any benchmark results for Mahout MatrixMultiplication? Thanks! Martin [1] [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L191-193] [2] [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L221-225] [3] [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L190-206] [4] [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L230-231] was: Hello, I think I have found two minor problems in *DistributedRowMatrix*. In [1] the condition is wrong, because (l x m) * (m x n) = (l x n). The condition should be like in [2]. And in *times*[3] the {{this.transpose()}} seems to be missing? (See [4]) Do you have any benchmark results for Mahout MatrixMultiplication? Thanks! Martin [1] [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L191-193] [2] [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L222-226] [3] [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L190-206] [4] [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L231-232] > Two minor problems in DistributedRowMatrix using MatrixMultiplication > --------------------------------------------------------------------- > > Key: MAHOUT-1266 > URL: https://issues.apache.org/jira/browse/MAHOUT-1266 > Project: Mahout > Issue Type: Bug > Components: Math > Affects Versions: 0.7 > Reporter: Martin Illecker > Priority: Trivial > Labels: newbie > Original Estimate: 10m > Remaining Estimate: 10m > > Hello, > I think I have found two minor problems in *DistributedRowMatrix*. > In [1] the condition is wrong, because (l x m) * (m x n) = (l x n). > The condition should be like in [2]. > And in *times*[3] the {{this.transpose()}} seems to be missing? (See [4]) > Do you have any benchmark results for Mahout MatrixMultiplication? > Thanks! > Martin > [1] > [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L191-193] > [2] > [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L221-225] > [3] > [https://github.com/apache/mahout/blob/trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java#L190-206] > [4] > [https://github.com/millecker/applications/blob/master/hadoop/rootbeer/matrixmultiplication/src/at/illecker/hadoop/rootbeer/examples/matrixmultiplication/DistributedRowMatrix.java#L230-231] -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira