I have a regression result with masked arrays that produces a masked array output, estm5.yhat, and I want to test equality to the benchmark case, estm1.yhat, with the asserts in numpy.testing, but I am getting strange results. checking for equality directly returns True, but the asserts in numpy.testing think that they are not equal. It seems the asserts use one of the masked (random) values in the comparison. Whats the trick to assert_almost_equal for masked arrays? Josef

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np.all(estm5.yhat == estm1.yhat) True

and they look the same:

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estm5.yhat.T masked_array(data = [[-- 3.72175928422 4.44050187015 3.86191008624 7.54173762712 3.52929761101 5.00953694359 5.19214323965 4.71500145194 8.22336216275 7.8884375775 5.24556560163 6.81814135969 7.65416592877 3.7608331097]], mask = [[ True False False False False False False False False False False False False False False]], fill_value=1e+020)

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estm1.yhat.T masked_array(data = [[-- 3.72175928422 4.44050187015 3.86191008624 7.54173762712 3.52929761101 5.00953694359 5.19214323965 4.71500145194 8.22336216275 7.8884375775 5.24556560163 6.81814135969 7.65416592877 3.7608331097]], mask = [[ True False False False False False False False False False False False False False False]], fill_value=1e+020)

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np.testing.assert_array_almost_equal(estm5.yhat, estm1.yhat) Traceback (most recent call last): File "<pyshell#253>", line 1, in <module> np.testing.assert_array_almost_equal(estm5.yhat, estm1.yhat) File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py",

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np.testing.assert_almost_equal(estm5.yhat, estm1.yhat) Traceback (most recent call last): File "<pyshell#254>", line 1, in <module> np.testing.assert_almost_equal(estm5.yhat, estm1.yhat) File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py",

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np.testing.assert_equal(estm5.yhat, estm1.yhat) Traceback (most recent call last): File "<pyshell#255>", line 1, in <module> np.testing.assert_equal(estm5.yhat, estm1.yhat) File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py",

using any np.testing.assert returns False line 310, in assert_array_almost_equal header='Arrays are not almost equal') File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py", line 299, in assert_array_compare raise ValueError(msg) ValueError: Arrays are not almost equal x: array([[ 6.1104881 ], [ 3.72175928], [ 4.44050187],... y: array([[ NaN], [ 3.72175928], [ 4.44050187],... line 208, in assert_almost_equal return assert_array_almost_equal(actual, desired, decimal, err_msg) File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py", line 310, in assert_array_almost_equal header='Arrays are not almost equal') File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py", line 299, in assert_array_compare raise ValueError(msg) ValueError: Arrays are not almost equal x: array([[ 6.1104881 ], [ 3.72175928], [ 4.44050187],... y: array([[ NaN], [ 3.72175928], [ 4.44050187],... line 180, in assert_equal return assert_array_equal(actual, desired, err_msg, verbose) File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py", line 303, in assert_array_equal verbose=verbose, header='Arrays are not equal') File "C:\Programs\Python25\lib\site-packages\numpy\testing\utils.py", line 295, in assert_array_compare raise AssertionError(msg) AssertionError: Arrays are not equal (mismatch 100.0%) x: array([[ 6.1104881 ], [ 3.72175928], [ 4.44050187],... y: array([[ NaN], [ 3.72175928], [ 4.44050187],...

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estm5.yhat == estm1.yhat masked_array(data = [[--] [True] [True] [True] [True] [True] [True] [True] [True] [True] [True] [True] [True] [True] [True]], mask = [[ True] [False] [False] [False] [False] [False] [False] [False] [False] [False] [False] [False] [False] [False] [False]], fill_value=1e+020)