cache dtype.__hash__ #5339
Description
It would be nice to cache the hash value of dtypes, since computation can be non-trivial for complex (e.g. structured) dtypes.
I would like to contribute this but I had some trouble running the test suite, and now I'm not able to build Numpy anymore:
$ python3.4 setup.py build
Running from numpy source directory.
Traceback (most recent call last):
File "setup.py", line 251, in <module>
setup_package()
File "setup.py", line 235, in setup_package
from numpy.distutils.core import setup
File "/home/antoine/np/numpy/distutils/__init__.py", line 37, in <module>
from numpy.testing import Tester
File "/home/antoine/np/numpy/testing/__init__.py", line 14, in <module>
from .utils import *
File "/home/antoine/np/numpy/testing/utils.py", line 17, in <module>
from numpy.core import float32, empty, arange, array_repr, ndarray
File "/home/antoine/np/numpy/core/__init__.py", line 14, in <module>
from . import multiarray
ImportError: cannot import name 'multiarray'