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

josef.pktd@gmai... josef.pktd@gmai...
Sat Sep 8 14:38:21 CDT 2012

On Sat, Sep 8, 2012 at 1:46 PM,  <josef.pktd@gmail.com> wrote:
> On Sat, Sep 8, 2012 at 1:33 PM, Matthew Brett <matthew.brett@gmail.com> wrote:
>> Hi,
>> On Sat, Sep 8, 2012 at 5:31 PM, Ralf Gommers <ralf.gommers@gmail.com> wrote:
>>> On Tue, Aug 14, 2012 at 3:35 PM, John Hassler <hasslerjc@comcast.net> wrote:
>>>> 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
>>> What are we going to do about this one? I'm tempted to open a ticket for it
>>> and mark it as knownfail on Windows for now, since it's a corner case.
>> I have noticed that windows SVD appears to give different answers from
>> repeated runs on the same matrix, differing in terms of sign flips,
>> but valid SVDs.  I've no idea why, but I had to adjust the tests in
>> our code to allow for this.
>> I guess we should make sure the returned results are correct, and fail
>> otherwise.  But maybe we do not require two runs to give the same
>> answer.  Could that explain the problem?
> I'm only paying partial attention and not up-to-date, just a few tries:

after installing rc2 into my 2.7.1 virtualenv, I cannot replicate any
errors, also not running the singular test directly

(py27b) E:\Josef\testing\tox\py27b\Scripts>easy_install

(py27b) E:\Josef\testing\tox\py27b\Scripts>python
Python 2.7.1 (r271:86832, Nov 27 2010, 18:30:46) [MSC v.1500 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import scipy
>>> scipy.__version__
>>> scipy.__file__
>>> scipy.test()

Ran 5486 tests in 56.394s
<nose.result.TextTestResult run=5486 errors=0 failures=0>

If I just unzip the superpack instead of installing the sse3, I get
only one failure

FAIL: test_basic.TestNorm.test_stable
Traceback (most recent call last):
  File "E:\Josef\testing\tox\py27b\lib\site-packages\nose-1.1.2-py2.7.egg\nose\case.py",
line 197, in runTest
  File "E:\Josef\testing\tox\py27b\lib\site-packages\scipy\linalg\tests\test_basic.py",
line 592, in
    assert_almost_equal(norm(a) - 1e4, 0.0, err_msg=msg)
  File "E:\Josef\testing\tox\py27b\lib\site-packages\numpy-1.6.2-py2.7-win32.egg\numpy\testing\utils.py",
line 468, in assert_almost_equal
    raise AssertionError(msg)
Arrays are not almost equal to 7 decimals
: Result should equal either 0.0 or 0.5 (depending on implementation of snrm2).
 ACTUAL: 0.4990234375

maybe some sse incompatibilities.

(I figured out how to install scipy into a virtualenv without
installing it into my main python first.)


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