[mlpack-svn] [MLPACK] #300: allknn fails for mnist8m dataset

MLPACK Trac trac at coffeetalk-1.cc.gatech.edu
Tue Nov 11 02:42:05 EST 2014


#300: allknn fails for mnist8m dataset
----------------------+-----------------------------------------------------
  Reporter:  rozyang  |        Owner:  rcurtin 
      Type:  defect   |       Status:  accepted
  Priority:  major    |    Milestone:          
 Component:  mlpack   |   Resolution:          
  Keywords:           |     Blocking:          
Blocked By:  302      |  
----------------------+-----------------------------------------------------

Comment (by rozyang):

 After using a 64-bit Armadillo, it seems the data loading is successful.
 But the program still crashes when computing K-nearest neighbors. Below is
 the output

 $ gdb ../../codes/others/mlpack-1.0.10/build/bin/allknn
 GNU gdb (GDB) Red Hat Enterprise Linux (7.2-64.el6_5.2)
 Copyright (C) 2010 Free Software Foundation, Inc.
 License GPLv3+: GNU GPL version 3 or later
 <http://gnu.org/licenses/gpl.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
 and "show warranty" for details.
 This GDB was configured as "x86_64-redhat-linux-gnu".
 For bug reporting instructions, please see:
 <http://www.gnu.org/software/gdb/bugs/>...
 Reading symbols from
 /triton/ics/project/bayes/rozyang/codes/others/mlpack-1.0.10/build/bin/allknn...done.
 (gdb) run -r mnist8m_T.csv -n mnist8m_3nn.csv -d mnist8m_3nn_distances.csv
 -k 3 -v
 Starting program:
 /triton/ics/project/bayes/rozyang/codes/others/mlpack-1.0.10/build/bin/allknn
 -r mnist8m_T.csv -n mnist8m_3nn.csv -d mnist8m_3nn_distances.csv -k 3 -v
 [Thread debugging using libthread_db enabled]
 [DEBUG] Compiled with debugging symbols.
 [INFO ] Loading 'mnist8m_T.csv' as CSV data.  Size is 8100000 x 784.
 [INFO ] Loaded reference data from 'mnist8m_T.csv' (8100000 x 784).
 [INFO ] Building reference tree...
 [INFO ] Trees built.
 [INFO ] Computing 3 nearest neighbors...

 Program received signal SIGSEGV, Segmentation fault.
 mlpack::neighbor::NearestNeighborSort::SortDistance (list=...,
 indices=..., newDistance=18.303005217723125)
     at
 /triton/ics/project/bayes/rozyang/codes/others/mlpack-1.0.10/src/mlpack/methods/neighbor_search/sort_policies/nearest_neighbor_sort.cpp:32
 32        if (newDistance > list[list.n_elem - 1])
 Missing separate debuginfos, use: debuginfo-install
 atlas-3.8.4-2.el6.x86_64 libxml2-2.7.6-17.el6_6.1.x86_64
 openblas-0.2.11-1.el6.x86_64

-- 
Ticket URL: <http://trac.research.cc.gatech.edu/fastlab/ticket/300#comment:8>
MLPACK <www.fast-lab.org>
MLPACK is an intuitive, fast, and scalable C++ machine learning library developed at Georgia Tech.


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