Summary:
`brew_test.py` is just plain broken. `core_test.py` doesn't work with pytest. `apmeter_test.py` and `top_k_test.py` don't work for CUDA builds.
Closes https://github.com/caffe2/caffe2/pull/765
Differential Revision: D5211817
Pulled By: Yangqing
fbshipit-source-id: 78ec5af35a3fa870978e4c9590210ade9e3bc5ac
Summary: Implements an APMeter operator (APMeterOp) to calculate AP for multilclass classification given prediction socres and labels. The Op takes a score tensor [nsamples x nclasses] and a label tensor [nsamples x nclasses], and outputs a float tensor of size nclasses as the AP for each class.
Reviewed By: akyrola
Differential Revision: D5082565
fbshipit-source-id: ae7304bc8fc999c361245b9aec38eb9a5f5eef4b
