[NumPy-Tickets] [NumPy] #1469: Matrix multiplication (dot) fails silently for large integers v1.3.0rc2

NumPy Trac numpy-tickets@scipy....
Fri Apr 30 15:20:27 CDT 2010


#1469: Matrix multiplication (dot) fails silently for large integers v1.3.0rc2
--------------------+-------------------------------------------------------
 Reporter:  gtpitt  |       Owner:  somebody
     Type:  defect  |      Status:  new     
 Priority:  normal  |   Milestone:          
Component:  Other   |     Version:          
 Keywords:          |  
--------------------+-------------------------------------------------------
 When multiplying 2 matrices with large integer values the following error
 was observed. Please note that no warning or error message was received.
 This is running in Eclipse Version: 3.4.1 Build id: M20080911-1700. Pydev
 v 1.4.6.2788.
 version 1.3.0rc2
 gm1 :
 [[      0       1]
  [      1 -157249]]

 gm2 :
 [[  8762 -28349]
  [-54857 177487]]

 gm = dot(gm2,gm1) (note the order, gm2 is first)

 [[     -28349   162893367]
  [     177487 -2139904344]]


 correct answer :
 [[     -28349   4457860663]
  [     177487 -27909708120]]

 4457860663 (34 bits) :
 100001001101101011000111000110111

-- 
Ticket URL: <http://projects.scipy.org/numpy/ticket/1469>
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