[MAHOUT-1630] Incorrect SparseColumnMatrix.numSlices() causes IndexException in toString()

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9
• Fix Version/s: 0.10.0
• Component/s: classic
• Labels: legacy math scala
• Assignee: Suneel Marthi
• Reporter: Oleg Nitz
• Created: 25/Nov/14 15:52
• Updated: 31/Jan/24 22:16
• Resolved: 08/Apr/15 05:23

Description

SparseColumnMatrix overrides the numSlices() method incorrectly: it returns numCols() instead of numRows().
As a result, AbstractMaxtrix.toString() for wide matrices throws an exception.
For example, this code:

Matrix matrix = new SparseColumnMatrix(1, 2);
matrix.toString();

causes

org.apache.mahout.math.IndexException: Index 1 is outside allowable range of [0,1)
at org.apache.mahout.math.MatrixVectorView.<init>(MatrixVectorView.java:42)
at org.apache.mahout.math.AbstractMatrix.viewRow(AbstractMatrix.java:290)
at org.apache.mahout.math.AbstractMatrix$1.computeNext(AbstractMatrix.java:68)
at org.apache.mahout.math.AbstractMatrix$1.computeNext(AbstractMatrix.java:59)
at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
at org.apache.mahout.math.AbstractMatrix.toString(AbstractMatrix.java:787)