[pypy-issue] [issue1302] numpypy arange difference from numpy
mikefc
tracker at bugs.pypy.org
Thu Oct 25 06:34:36 CEST 2012
New submission from mikefc <coolbutuseless at gmail.com>:
I was looking at the equivalent python benchmark for the julia language:
https://raw.github.com/JuliaLang/julia/master/test/perf/perf.py
The mandelperf() benchmark (runnable snippet attached) returns slightly different
results, because, ultimately, there's a slight difference in the "almost 0" values
returned by numpy.arange() i.e. 6.38378239e-16 != 1.77635684e-15
Should we expect these "almost zero" values to be the same?
-------------------------------
pypy (latest nightly)
-------------------------------
>>>> numpy.arange(-2, 0.5, 0.1, dtype='f8')
array([ -2.00000000e+00, -1.90000000e+00, -1.80000000e+00,
-1.70000000e+00, -1.60000000e+00, -1.50000000e+00,
-1.40000000e+00, -1.30000000e+00, -1.20000000e+00,
-1.10000000e+00, -1.00000000e+00, -9.00000000e-01,
-8.00000000e-01, -7.00000000e-01, -6.00000000e-01,
-5.00000000e-01, -4.00000000e-01, -3.00000000e-01,
-2.00000000e-01, -1.00000000e-01, 6.38378239e-16,
1.00000000e-01, 2.00000000e-01, 3.00000000e-01,
4.00000000e-01])
numpy v1.6
-------------------------------
>>> numpy.arange(-2, 0.5, 0.1, dtype='f8')
array([ -2.00000000e+00, -1.90000000e+00, -1.80000000e+00,
-1.70000000e+00, -1.60000000e+00, -1.50000000e+00,
-1.40000000e+00, -1.30000000e+00, -1.20000000e+00,
-1.10000000e+00, -1.00000000e+00, -9.00000000e-01,
-8.00000000e-01, -7.00000000e-01, -6.00000000e-01,
-5.00000000e-01, -4.00000000e-01, -3.00000000e-01,
-2.00000000e-01, -1.00000000e-01, 1.77635684e-15,
1.00000000e-01, 2.00000000e-01, 3.00000000e-01,
4.00000000e-01])
----------
files: mandelperf.py
messages: 4907
nosy: mikefc, pypy-issue
priority: bug
status: unread
title: numpypy arange difference from numpy
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