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IDProjectCategoryView StatusLast Update
0000715OpenFOAMBugpublic2013-01-02 17:09
Reportermichele Assigned Touser17 
PrioritynormalSeverityminorReproducibilityhave not tried
Status resolvedResolutionfixed 
PlatformLinuxOSOpenSuseOS Version11.3
Summary0000715: wrong SVD outputs, for certain matrix configurations
DescriptionI encountered wrong outputs of the SVD decomposition, that occur on some particular input matrix configurations.
Steps To ReproduceHere attached a simple test, run:
wmake; SVDtest

The output is uncorrect (wrong U, S, V and pseudoinverse). Here below the wrong output produced by the program:
U(A) : 3 3((0 -0.457702 0.889106)(-0.361655 -0.828924 -0.426721)(0.932312 -0.321549 -0.16553))
S(A) : 3(758.049 281.274 808.55)
V(A) : 3 3((-1 0 0)(-0 -0.932312 0.361655)(-0 -0.361655 -0.932312))
pseudoinverse(A) : 3 3((0 0.000477086 -0.00122988)(0.00191479 0.00255669 0.000991769)(-0.000436698 0.00155785 0.000604307))


If line 35 is commented, and line 36 is uncommented out (the vector F has just one less digit, so the output should be essentially the same) and the test is re-run, the output is now correct; for instance the pseudoinverse:

pseudoinverse(A) : 3 3((-9.85333e-10 0.000419348 -0.00108105)(-0.000419351 7.28519e-10 0.000430246)(0.00108105 -0.000430245 2.56813e-10))

is confirmed by matlab (whose output is practically identical for both cases):
pinv(A)
  -8.6139e-20 4.1935e-04 -1.0810e-03
  -4.1935e-04 -2.7105e-20 4.3025e-04
   1.0810e-03 -4.3025e-04 -1.0842e-19
TagsNo tags attached.

Activities

michele

2013-01-02 14:24

reporter  

SVDtest.tar.gz (1,502 bytes)

user17

2013-01-02 17:09

  ~0001852

Resolved by commit c79762488bb97ec8cb786ecff81560e3409762f0

Issue History

Date Modified Username Field Change
2013-01-02 14:24 michele New Issue
2013-01-02 14:24 michele File Added: SVDtest.tar.gz
2013-01-02 15:41 user17 Assigned To => user17
2013-01-02 15:41 user17 Status new => assigned
2013-01-02 17:09 user17 Note Added: 0001852
2013-01-02 17:09 user17 Status assigned => resolved
2013-01-02 17:09 user17 Fixed in Version => 2.1.x
2013-01-02 17:09 user17 Resolution open => fixed