This is the release note of v5.1.0. See [here](https://github.com/chainer/chainer/milestone/82?closed=1) for the complete list of solved issues and merged PRs.
New Features
- Added support for float dtypes in some functions
- `F.negative_sampling` (5593)
- `F.scatter_add` and `F.get_item` (5594)
Enhancements
- Avoid unnecessary copy in `ndarray.astype` (5623)
- Add `compute_stream` argument in `ConcatWithAsyncTransfer` to allow more overlap between computation and transfer in CUDA (5684, thanks anaruse!)
- Add gradient consistency checks in `numerical_grad` (5705)
- Code enhancements
- Avoid cuDNN handle around `DropoutStates` (5644)
- Import `testing/backend.py` definitions in `testing/__init__.py` (5639)
- Simplify pooling and softmax with cuDNN (5637, 5672)
- More consistent use of `Variable.array` in codes under links (5689, thanks crcrpar!)
- Use automatic broadcasting instead of `F.repeat` (5708)
Bug Fixes
- Fix `D.Uniform.log_prob` to avoid returning -inf at boundary (5550)
- Fix `reporter.Summary` float value deserialization (5584)
- Fix `F.negative_sampling` output dtype in CPU mode (5625)
Documentation
- Add ChainerMN paper to references (5583)
- Fix docstring of `F.forget` (5588, thanks fiarabbit!)
- Fix typo in updaters (5598, thanks okayu9!)
- Update documentation for iDeep constraints (5601)
- Fix the method name in the extension guide (5605, thanks lehy!)
- Update `F.roi_average_align_2d` doc to refer wrapper function (5617, thanks knorth55!)
- Update installation guide of numpy with openblas on macOS (5630)
- Fix a typo in `Chain` example code (5655)
- Fix a typo in `chainer.distributions` documentation (5661)
- Fix typo in `L.ResNetLayers` (5667, thanks takaaki82!)
- Minor typo correction (in docs/variables). (5671, thanks grigorisg9gr!)
- Add links to ChainerCV documentation (5677)
- Fix typo in docstrings (5679)
- Add documentation of `ndarray` (5704)
- Fix docs for `backprop_step` (5710)
- Make docs in `chainer.distributions` refer `ndarray` (5719)
Examples
- Use `SerialIterator` in `train_mnist_custom_loop.py` (5544)
Test
- Fix test warnings in NumPy 1.15 (5599)
- Fix test of `F.rrelu` (5673)
- Ignore h5py warning in Python 3.7 (5694)
- Fix regex of protobuf modules warned by Python 3.7 (5711)
Others
- Update style check tools to the versions compatible with pycodestyle 2.4 (5715)