[SciPy-user] Installation on dual opteron ...

Robert Kern rkern at ucsd.edu
Tue Sep 27 16:46:49 CDT 2005


Stephen Walton wrote:
> Arnd Baecker wrote:
> 
>> scipy.test(10) gives:
>>
>> ======================================================================
>> FAIL: check_round (scipy.special.basic.test_basic.test_round)
>> ----------------------------------------------------------------------
>> Traceback (most recent call last):
>>  File
>> "/scr/python3/lib/python2.4/site-packages/scipy/special/tests/test_basic.py",
>>
>> line 1789, in check_round
>>    assert_array_equal(rnd,rndrl)
>>  File "/scr/python3/lib/python2.4/site-packages/scipy_test/testing.py",
>> line 715, in assert_array_equal
>>    assert cond,\
>> AssertionError:
>> Arrays are not equal (mismatch 25.0%):
>>        Array 1: [10 10 11 11]
>>        Array 2: [10 10 10 11]
>>  
> I'm getting this same error on my i386 systems using Absoft Fortran and
> Fedora Core 4, so this problem is not unique to the Opteron
> architecture.  I can't help with the X11 link problem, I'm afraid, as I
> don't see it on my i386 systems.

We've run into this several times before. The test is right according to
the documentation.

In [5]: round?
Type:           ufunc
String Form:    <ufunc 'round'>
Namespace:      Interactive
Docstring:
    y=Returns the nearest integer to x as a double precision
    floating point result.  If x ends in 0.5 exactly, the
    nearest even integer is chosen.

That's the round() from scipy.special which ought to be the one being
called by this check_round(). You might want to add a "print round"
statement to the check_round() method just to make sure that it is the
ufunc from scipy.special and not the alias to around() from Numeric
which follows Python's round-up-on-0.5 behavior.

The last time we came across it, I had Fernando check a C program that
tries the underlying Cephes routine, and it gives the expected answer.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter



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