[Insight-users] No test for svd?

[Luis Ibanez]

Hi Frank,

Your report is a bit confusing.

You said that

   " When updating any pipeline that has
     a particular image as an input,
     I get the following message printed to standard error:"


so it seems that the problem is related to the image
itself.

Since you are using an oriented image, it is reasonable
to assume that the problem is related to the computation
of the inverse matrix of the direction cosines.

Chances are that your directions cosines are badly conditioned,
for example they may be coplanar instead of forming an orthogonal
system. That may prompt the error in svd.

Have you verified the rank of the matrix of direction cosines ?


 >     Direction:
 >   0.696096 -0.0991128 -0.711074
 >   0.717949 0.0960961 0.689431
 >   2.13894e-08 -0.990425 0.13805



Please let us know,



   Thanks


       Luis


------------------
Frank Miller wrote:
> Greetings,
> 
> Im having a very strange problem with the svd algorithm. My experience 
> is consistent with the problem mentioned in the comments at line 92 in 
> the file
> 
>   Utilities/vxl/core/vnl/algo/vnl_svd.txx
> 
> If this is the source of my problem, the comments state that the 
> "core/vnl/tests/test_svd" should have failed. However, I cant find this 
> test. I turned BUILD_TESTING on and there is no "test_svd". There is a 
> "vnl_test_all" which when run states that
> 
>   The registered test names are:
>      test_bignum
>      test_complex
>      test_inverse
>      test_diag_matrix
>      test_file_matrix
>      test_finite
>      test_math
>      test_matrix
>      test_matrix_exp
>      test_matrix_fixed
>      test_matrix_fixed_ref
>      test_numeric_traits
>      test_rational
>      test_real_polynomial
>      test_resize
>      test_sample
>      test_sym_matrix
>      test_transpose
>      test_fastops
>      test_vector
>      test_vector_fixed_ref
>      test_gamma
>      test_random
>      test_arithmetic
>      test_hungarian_algorithm
>      test_integrant
>      test_bessel
> 
> all of which pass on my system.
> 
> How can I run this test on my system? Is this test not being run by 
> Dart? Any help would be much appreciated,
> 
> 
> Below is some more details if you are interested.
> 
> My system is 32bit Linux, my cpu is Intel Xeon, my compiler is 
> gcc-4.1.1, and Im using itk-2.8.1.
> 
> When updating any pipeline that has a particular image as an input, I 
> get the following message printed to standard error:
> 
>   /home/frank/opt/src/itk/2.8.1/InsightToolkit-2.8.1/Utilities/vxl/core/
>   vnl/algo/vnl_svd.txx: suspicious return value (3) from SVDC
>   /home/frank/opt/src/itk/2.8.1/InsightToolkit-2.8.1/Utilities/vxl/core/
>   vnl/algo/vnl_svd.txx: M is 3x3
>   M = [ ...
>    0.9788850881159 -0.1393774186727 -5.6885917960696
>    1.0096153244376  0.1351351488847  5.5154448566180
>    0.0000000300788 -1.3927854783833  1.1043995835373  ]
> 
> The correct singular values for M are, according to octave, 8.0000, 
> 1.4063, 1.4062.
> 
> Here is a trace of the image:
> 
>   OrientedImage (0x83f0000)
>     RTTI typeinfo:   itk::OrientedImage<int, 3u>
>     Reference Count: 6
>     Modified Time: 714
>     Debug: Off
>     Observers:
>       none
>     Source: (0x83eb4c8)
>     Source output index: 0
>     Release Data: On
>     Data Released: False
>     Global Release Data: Off
>     PipelineMTime: 238
>     UpdateMTime: 715
>     LargestPossibleRegion:
>       Dimension: 3
>       Index: [0, 0, 0]
>       Size: [256, 256, 17]
>     BufferedRegion:
>       Dimension: 3
>       Index: [0, 0, 0]
>       Size: [256, 256, 17]
>     RequestedRegion:
>       Dimension: 3
>       Index: [0, 0, 0]
>       Size: [256, 256, 17]
>     Spacing: [1.40625, 1.40625, 7.99999]
>     Origin: [-37.7846, -241.523, 175.909]
>     Direction:
>   0.696096 -0.0991128 -0.711074
>   0.717949 0.0960961 0.689431
>   2.13894e-08 -0.990425 0.13805
> 
>     PixelContainer:
>       ImportImageContainer (0x83f01b8)
>         RTTI typeinfo:   itk::ImportImageContainer<unsigned long, int>
>         Reference Count: 1
>         Modified Time: 288
>         Debug: Off
>         Observers:
>           none
>         Pointer: 0x83f01e8
>         Container manages memory: true
>         Size: 1114112
>         Capacity: 1114112
> 
> Thanks,
> 
> Frank
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