[ https://issues.apache.org/jira/browse/MAHOUT-1221?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Maysam Yabandeh updated MAHOUT-1221: ------------------------------------ Attachment: MAHOUT-1221.patch MAHOUT-1221.patch fix the typo in patch name > SparseMatrix.viewRow is sometimes readonly > ------------------------------------------ > > Key: MAHOUT-1221 > URL: https://issues.apache.org/jira/browse/MAHOUT-1221 > Project: Mahout > Issue Type: Bug > Components: Math > Affects Versions: 0.7 > Reporter: Maysam Yabandeh > Priority: Minor > Labels: patch > Fix For: 0.7, 0.8 > > Attachments: MAHOUT-1221.patch, MAHOUT-1221.patch > > > The implementation returns a new vector if it already does not exist. But it > does not add the new vector to the matrix. So, the later changes will not be > reflected in the matrix. > {code:java} > if (res == null) { > res = newRandomAccessSparceVector(columnSize()); > //now the row must be added by assignRow(row, res); > } > return res; > {code} > An example in which this bug manifests is the following: > {code:title=QRDecomposition.java} > x.viewRow(k).assign(y.viewRow(k), Functions.plusMult(1 / r.get(k, k))); > {code} > where Matrix x is not updated if it is an instance of SparseMatrix. -- 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