[SciPy-User] ANN: SciPy 0.11.0 release candidate 2

[John Hassler]

On 8/14/2012 7:21 AM, Pauli Virtanen wrote:
> Ralf Gommers <ralf.gommers <at> gmail.com> writes:
> [clip]
>> Does anyone have an idea about that test_singular failure?
> That's very likely some problem with the underlying LAPACK library.
> I think the problem solved is close to a numerical instability.
>
> The failing comparison compares eigenvalues computed by
>
>      eig(A, B)
>      eig(A, B, left=False, right=False)
>
> which differ solely in passing 'N' vs. 'V' to DGGEV. The eigenvalue
> property of the former is also checked and seems to pass. Interestingly,
> the result obtained from the two seems to differ (therefore, the latter
> is probably wrong), which appears to point to a LAPACK issue.
>
> Here, it would be interesting to know if the problem occurs with
> the official Scipy binaries, or something else.
>

I installed rc2 on Python 2.7.3.  Same problem.  I get the test_singular 
error on some, but not all, of the runs.  Both are win32-superpack from 
http://sourceforge.net/projects/scipy/files/scipy/0.11.0rc2/.

The error occurs on less than half but more than 1/3 (based on a very 
small sample) of the runs on both 2.7 and 3.2.

I've been working on computers for more than 50 years.  Somehow, I had 
developed the delusion that they were deterministic .....
john

------------- Python 2.7 --------------------
 >>> import scipy
 >>> scipy.test()
Running unit tests for scipy
NumPy version 1.6.2
NumPy is installed in C:\Python27\lib\site-packages\numpy
SciPy version 0.11.0rc2
SciPy is installed in C:\Python27\lib\site-packages\scipy
Python version 2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit 
(Intel)]
nose version 0.11.2

======================================================================
FAIL: test_decomp.TestEig.test_singular
Test singular pair
----------------------------------------------------------------------
Traceback (most recent call last):
   File 
"C:\Python27\lib\site-packages\nose-0.11.2-py2.7.egg\nose\case.py", line 
186, in runTest
     self.test(*self.arg)
   File 
"C:\Python27\lib\site-packages\scipy\linalg\tests\test_decomp.py", line 
201, in test_singular
     self._check_gen_eig(A, B)
   File 
"C:\Python27\lib\site-packages\scipy\linalg\tests\test_decomp.py", line 
188, in _check_gen_eig
     err_msg=msg)
   File "C:\Python27\lib\site-packages\numpy\testing\utils.py", line 
800, in assert_array_almost_equal
     header=('Arrays are not almost equal to %d decimals' % decimal))
   File "C:\Python27\lib\site-packages\numpy\testing\utils.py", line 
636, in assert_array_compare
     raise AssertionError(msg)
AssertionError:
Arrays are not almost equal to 6 decimals

array([[22, 34, 31, 31, 17],
        [45, 45, 42, 19, 29],
        [39, 47, 49, 26, 34],
        [27, 31, 26, 21, 15],
        [38, 44, 44, 24, 30]])
array([[13, 26, 25, 17, 24],
        [31, 46, 40, 26, 37],
        [26, 40, 19, 25, 25],
        [16, 25, 27, 14, 23],
        [24, 35, 18, 21, 22]])
(mismatch 25.0%)
  x: array([ -2.45037885e-01 +0.00000000e+00j,
          5.17637463e-16 -4.01120590e-08j,
          5.17637463e-16 +4.01120590e-08j,   2.00000000e+00 
+0.00000000e+00j])
  y: array([ -3.74550285e-01 +0.00000000e+00j,
         -5.17716907e-17 -1.15230800e-08j,
         -5.17716907e-17 +1.15230800e-08j,   2.00000000e+00 
+0.00000000e+00j])

----------------------------------------------------------------------
Ran 5490 tests in 103.250s

FAILED (KNOWNFAIL=14, SKIP=36, failures=1)
<nose.result.TextTestResult run=5490 errors=0 failures=1>
 >>>

-------------- Python 3.2 --------------
 >>> scipy.test()
Running unit tests for scipy
NumPy version 1.6.2
NumPy is installed in C:\Python32\lib\site-packages\numpy
SciPy version 0.11.0rc2
SciPy is installed in C:\Python32\lib\site-packages\scipy
Python version 3.2.3 (default, Apr 11 2012, 07:15:24) [MSC v.1500 32 bit 
(Intel)]
nose version 1.0.0

======================================================================
FAIL: test_decomp.TestEig.test_singular
----------------------------------------------------------------------
Traceback (most recent call last):
   File 
"C:\Python32\lib\site-packages\nose-1.0.0-py3.2.egg\nose\case.py", line 
188, in runTest
     self.test(*self.arg)
   File 
"C:\Python32\lib\site-packages\scipy\linalg\tests\test_decomp.py", line 
201, in test_singular
     self._check_gen_eig(A, B)
   File 
"C:\Python32\lib\site-packages\scipy\linalg\tests\test_decomp.py", line 
188, in _check_gen_eig
     err_msg=msg)
   File "C:\Python32\lib\site-packages\numpy\testing\utils.py", line 
800, in assert_array_almost_equal
     header=('Arrays are not almost equal to %d decimals' % decimal))
   File "C:\Python32\lib\site-packages\numpy\testing\utils.py", line 
636, in assert_array_compare
     raise AssertionError(msg)
AssertionError:
Arrays are not almost equal to 6 decimals

array([[22, 34, 31, 31, 17],
        [45, 45, 42, 19, 29],
        [39, 47, 49, 26, 34],
        [27, 31, 26, 21, 15],
        [38, 44, 44, 24, 30]])
array([[13, 26, 25, 17, 24],
        [31, 46, 40, 26, 37],
        [26, 40, 19, 25, 25],
        [16, 25, 27, 14, 23],
        [24, 35, 18, 21, 22]])
(mismatch 25.0%)
  x: array([ -2.450e-01 +0.000e+00j,   5.176e-16 -4.011e-08j, 5.176e-16 
+4.011e-08j,
          2.000e+00 +0.000e+00j])
  y: array([ -3.746e-01 +0.000e+00j,  -5.177e-17 -1.152e-08j, -5.177e-17 
+1.152e-08j,
          2.000e+00 +0.000e+00j])