Bug#831541: theano: single GradientError and WrongValues in tests on s390x

[Daniel Stender]

Source: theano
Version: 0.8.2-2
Severity: normal

The tests on s390x came up with three single errors (shortened) [1]:

<cut>
ERROR: test_grad (theano.sparse.tests.test_basic.SamplingDotTester)
----------------------------------------------------------------------
GradientError: GradientError: numeric gradient and analytic gradient exceed tolerance:
        At position 0 of argument 0,
            abs. error = 4.801748,  abs. tolerance = 0.000100
            rel. error = 1.000000,  rel. tolerance = 0.000100
Exception args: 
The error happened with the following inputs:, [array([[ 4.,  2.,  2.],
       [ 0.,  1.,  3.],
       [ 1.,  0.,  0.],
</cut>

<cut>
ERROR: test_op (theano.sparse.tests.test_basic.SamplingDotTester)
----------------------------------------------------------------------
WrongValue: WrongValue
           : shape, dtype, strides, min, max, n_inf, n_nan:
  Expected : (4, 5) float64 (40, 8) 0.0 28.0 0 0 
  Value    : (4, 5) float64 (40, 8) 0.0 0.0 0 0 
  expected    : [[ 28.   0.   0.   0.   0.]
 [ 12.   9.  11.   0.   0.]
 [  4.   1.   0.   2.   0.]
 [  0.   8.   0.   0.   0.]]
</cut>

</cut>
ERROR: test (theano.sparse.tests.test_basic.UsmmTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/«PKGBUILDDIR»/theano/sparse/tests/test_basic.py", line 1458, in test
    utt.assert_allclose(f_a_out, f_b_out, rtol=rtol, atol=atol)
  File "/«PKGBUILDDIR»/theano/tests/unittest_tools.py", line 339, in assert_allclose
    raise WrongValue(val1, val2, rtol, atol)
WrongValue: WrongValue
           : shape, dtype, strides, min, max, n_inf, n_nan:
  Expected : (10, 200) float32 (800, 4) -0.999263 0.999721 0 0 
  Value    : (10, 200) float32 (800, 4) -20.3578 20.3085 0 0 
  expected    : [[ 0.43297213 -0.99617213 -0.94651264 ...,  0.90926737  0.87269104
   0.18024164]
</cut>

The same errors occurs on ppc64 [2].

This is a regression from 0.8.2-2 (0.8.2-1 was build with `FAST_COMPILE` and this didn't
came up then). dh_auto_test is temporarily failsafed, this is going to be removed when
this problem is solved.

Thanks,
DS

[1] https://buildd.debian.org/status/fetch.php?pkg=theano&arch=s390x&ver=0.8.2-2&stamp=1468619676

[2] https://buildd.debian.org/status/fetch.php?pkg=theano&arch=ppc64&ver=0.8.2-3&stamp=1468725341

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.5.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.utf8, LC_CTYPE=de_DE.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)