On Mon, Apr 11, 2011 at 12:54 PM, Skipper Seabold <jsseab...@gmail.com>wrote:
> All, > > We noticed some failing tests for statsmodels between numpy 1.5.1 and > numpy >= 1.6.0. These are the versions where I noticed the change. It > seems that when you divide a float array and multiply by a boolean > array the answers are different (unless the others are also off by > some floating point). Can anyone replicate the following using this > script or point out what I'm missing? > > import numpy as np > print np.__version__ > np.random.seed(12345) > > test = np.random.randint(0,2,size=10).astype(bool) > t = 1.345 > arr = np.random.random(size=10) > > arr # okay > t/arr # okay > (1-test)*arr # okay > (1-test)*t/arr # huh? > > Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) > [GCC 4.4.3] on linux2 > Type "help", "copyright", "credits" or "license" for more information. > >>> import numpy as np > >>> print np.__version__ > 2.0.0.dev-fe3852f > >>> np.random.seed(12345) > >>> > >>> test = np.random.randint(0,2,size=10).astype(bool) > >>> t = 1.345 > >>> arr = np.random.random(size=10) > >>> > >>> arr # okay > array([ 0.5955447 , 0.96451452, 0.6531771 , 0.74890664, 0.65356987, > 0.74771481, 0.96130674, 0.0083883 , 0.10644438, 0.29870371]) > >>> t/arr # okay > array([ 2.25843668, 1.39448393, 2.05916589, 1.7959515 , > 2.0579284 , 1.79881418, 1.39913718, 160.342421 , > 12.63570742, 4.50278968]) > >>> (1-test)*arr # okay > array([ 0.5955447 , 0. , 0. , 0. , 0.65356987, > 0. , 0.96130674, 0.0083883 , 0. , 0.29870371]) > >>> (1-test)*t/arr # huh? > array([ 2.25797754, 0. , 0. , 0. , > 2.05751003, 0. , 1.39885274, 160.3098235 , > 0. , 4.50187427]) > > Looks like it is going through float16: In [2]: float16(1.345)/0.5955447 Out[2]: 2.25797754979601 The scalar 1.345 should be converted to double and that isn't happening. <snip> Chuck
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