NER example: fix metrics computation

[WilliamTambellini]

Description

NER example: fix metrics computation

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [MXNET-$JIRA_ID], where $JIRA_ID refers to the relevant JIRA issue created (except PRs with tiny changes)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at http://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$PR_ID/$BUILD_ID/index.html
• To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

• Fix metrics computation

Comments

• this change is backward compatible

[abhinavs95]

Thanks for the fix @WilliamTambellini

@mxnet-label-bot add [Example, Python, pr-awaiting-review]

[szha]

Suggested change

	logging.getLogger().info("build_vocab: word_counts=%d" % (len(word_counts)))
	logging.info("build_vocab: word_counts=%d", len(word_counts))

[WilliamTambellini]

@szha done

[vandanavk]

@piyushghai @abhinavs95 @karan6181 for review

[szha]

@WilliamTambellini seems that there's one more to fix for the lazy logging (the open comment).

[WilliamTambellini]

@WilliamTambellini seems that there's one more to fix for the lazy logging (the open comment).

done

[WilliamTambellini]

hum the unix-gpu job failed with
Failed: 1
Warnings: 4
Skipped: 2
Error: Test failures
Execution halted
Makefile:677: recipe for target 'rpkgtest' failed
make: *** [rpkgtest] Error 1

build.py: 2019-06-20 17:34:39,235Z CRITICAL Execution of ['/work/runtime_functions.sh', 'unittest_ubuntu_gpu_R'] failed with status: 2

Is that job supposed to pass ?

[szha]

@WilliamTambellini I triggered these builds again.

[WilliamTambellini]

@szha tks, it's better but now unix-cpu failed.

[karan6181]

@WilliamTambellini is this PR good to go for merge? I see all CI test are passing.

[WilliamTambellini]

@szha yes, it was just waiting for CI to pass. Tks.