On Fri, Oct 25, 2013 at 7:07 AM, Andrew Straw <dr.andrew.st...@gmail.com>wrote:
> Hi, > > I found an unexpected difference from numpy 1.7.1 and 1.8.0rc2 with Python > 3.3.2 on Ubuntu 12.04 (amd64). Here is the test program: > > import numpy as np > print(np.__version__) > K = np.array([[ 0. , 0. , 0. , 0. ], > [-0.33333333, 0. , 0. , 0. ], > [ 0.33333333, -0.33333333, 0. , 0. ], > [ 0.33333333, -0.33333333, 0.33333333, 0. ]]) > w, V = np.linalg.eigh(K) > print('w') > print(w) > > with numpy 1.7.1: > > 1.7.1 > w > [-0.33333333 -0.33333333 -0.33333333 0.99999999] > > with numpy 1.8.0rc2: > > 1.8.0rc2 > w > [ 0. 0. 0. 0.] > This appears to have gotten fixed since rc2: In [1]: K = np.array([[ 0. , 0. , 0. , 0. ], [-0.33333333, 0. , 0. , 0. ], [ 0.33333333, -0.33333333, 0. , 0. ], [ 0.33333333, -0.33333333, 0.33333333, 0. ]]) In [2]: eigh(K) Out[2]: (array([-0.33333333, -0.33333333, -0.33333333, 0.99999999]), array([[-0.78251031, 0.37104402, 0.00198815, 0.5 ], [-0.29974269, 0.03728557, 0.81164285, -0.5 ], [ 0.54246491, 0.46764373, 0.48686874, 0.5 ], [-0.05969728, -0.80140218, 0.32278596, 0.5 ]])) In [3]: np.__version__ Out[3]: '1.8.0.dev-ced0a94' Could you try the current 1.8.x version on github and see if the problem persists? Chuck
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