[NumPy-Tickets] [NumPy] #1364: segfault in numpy.dot for large arrays

NumPy Trac numpy-tickets@scipy....
Sun Jan 17 16:31:24 CST 2010


#1364: segfault in numpy.dot for large arrays
--------------------------+-------------------------------------------------
 Reporter:  QuestionMark  |       Owner:  somebody
     Type:  defect        |      Status:  new     
 Priority:  normal        |   Milestone:  1.4.0   
Component:  Other         |     Version:  1.3.0   
 Keywords:                |  
--------------------------+-------------------------------------------------
 Hello,

 I've encountered a segfault in numpy when trying to compute a dot product
 for two arrays - see code below. The problem only seems to occur when the
 arrays reach a certain size. I'm using Numpy version 1.3.0, installed via
 macports, on a 2.33 GHz Intel Core2 Duo Macbook Pro.

 Example code:

 import numpy as N
 print 'Demonstration of Numpy Bug:'
 print 'loading X (random numbers)'
 SzList = [10,20,30,40,50,60,70,80,90,100]
 for Sz in SzList:
         print 'X size = %d,%d'%(300,Sz)
         X = N.random.rand(300,Sz)
         Y = N.random.rand(300,3)
         print 'Attempting dot product of X and Y'
         N.dot(X.T,Y)
         print 'Finished without bug.'

 Result (run through gdb):
 (There were a number of warnings like this - so many that they  went off
 the top of the screen and I couldn't copy them all. This  was typical of
 the warnings.)

 Reading symbols for shared libraries warning: Could not find object file
 "/opt/local/var/macports/build_opt_local_var_macports_sources_rsync.macports.org_release_ports_lang_python26/work/Python-2.6.4/build/temp.macosx-10.5-i386-2.6/opt/local/var/macports/build_opt_local_var_macports_sources_rsync.macports.org_release
 _ports_lang_python26/work/Python-2.6.4/Modules/_collectionsmodule.o" - no
 debug information available for
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_lang_python26/work/Python-2.6.4/Modules/_collectionsmodule.c".

 . done
 Demonstration of Numpy Bug:
 loading X (random numbers)
 X size = 300,10
 Attempting dot product of X and Y
 Finished without bug.
 X size = 300,20
 Attempting dot product of X and Y
 Finished without bug.
 X size = 300,30
 Attempting dot product of X and Y
 Finished without bug.
 X size = 300,40
 Attempting dot product of X and Y
 Finished without bug.
 X size = 300,50
 Attempting dot product of X and Y
 Finished without bug.
 X size = 300,60
 Attempting dot product of X and Y

 Program received signal EXC_BAD_ACCESS, Could not access memory.
 Reason: 13 at address: 0x00000000
 [Switching to process 55933 thread 0x117]
 0x01038884 in ATL_dupMBmm0_2_0_b0 ()

 Help please (and thanks!),

 Mark

-- 
Ticket URL: <http://projects.scipy.org/numpy/ticket/1364>
NumPy <http://projects.scipy.org/numpy>
My example project


More information about the NumPy-Tickets mailing list