indexing with broadcasting (#1639)

* Implemented `_broadcast_indexes` in Variable.py

* Diagonal indexing for Variable.

* update _broadcast_indexes. update tests.

* Support basic boolean indexing.

* tests for dask-based Variable

* Explicitly mark xfail flags

* orthogonal indexing for dask.

* Refactor DaskArrayAdapter

* Added MissingDimensionsError. Improve DaskIndexingAdapter, Variable.__getitem__

* use `np.arange(*slice.indices(size))` rather than `np.arange(size)[slice]`.

* Add orthogonalize_indexers

* A bug fix.

* Working with LazilyIndexedArray

* Fix in LazilyIndexedArray.

* add @requires_dask in test_variable

* rename orthogonalize_indexers -> unbroadcast_indexers

* Wrap LazilyIndexedArray so that it accepts broadcasted-indexers

* small rename

* Another small fix

* Remove unused function.

* Added _broadcast_indexes_1vector

* Minor fix

* Avoid doubly wrapping by LazilyIndexedArray

* General orthogonal indexing for dask array.

* Added base class IndexableArrayAdapter

* Deprecate _unbroadcast_indexers and support IndexerTuple classes

* removed unintended prints.

* Some clean up.

* Some small fix.

* Care for boolean array.

* Always map boolean index to integer array.

* Takes care of boolean index in test_indexing

* replace self.assertTrue by assert

* Fix based on shoyer's comments.

* Added `to_tuple()` method to IndexerTuple class.

* Removed: 'orthogonal_indexer', 'canonicalize_indexer'

* update IndexVariable.__getitem__

* Made to_tuple function.

* BASIC_INDEXING_TYPES

* Removed unused function from tests.

* assert -> raise

* Update Dataset.isel

* Use `merge_variables` in checking the consistency.

* Cleanup Dataset.__getitem__

* Add comment about why align() is unneeded

* Ensure correct tests are run in test_variable.py

* Support pointwise indexing with dask

* Add a vindex routine for np.ndarray

* Add an OrderedSet to xarray.core.utils

* Support dask and numpy vindex with one path

* Fix test failures

* working with `Dataset.sel`

* Added more tests

* Changes per review

* Restore `isel_points`. Remove automatic tuple conversion for `sel`

* Some clean up

* Supported indexing by a scalar Variable

* Supported the indexing by DataArray with coordinates.

* Update DataArray.loc and DataArray.sel to use Dataset.loc and Dataset.sel

* Added inhouse normalize_axis_index

* Support an integer key for _advanced_indexer_subspaces

* Add warning for coordinate conflict.

* Warning changes DeprecationWarning -> FutureWarning.

* fix related to pytest.warns

* Another fix related to warning.

* Raise an Error for confusing indexing type

* Minor fix

* Test for indexing by a scalar coordinate.

* Modified test

* Remove too specialized errorning

* Working with docs

* Found a bug in as_variable

* Working with docs

* Enable indexing IndexVariable by multi-dimensional Variable.

* Found a bug in indexing np.ndarray

* Added a test for boolean-DataArray indexing.

* Make sure assignment certainly works.

* Added assignment section

* pep8

* Remove unused tests.

* Add more docs.

* Api.rst changed

* Add link in whats-new

* Small format cleanup

* allow positional indexing with unsigned integer types

* Catch up to the previous merge.

* workaround for daskarray with uint indexer.

* Add a section about assignment, full indexing rules.

* warning added for reindex for DataArray indexers.

* Move warning in alignment.reindex_variables.

* + Change API to attach non-dimensional coordinates.
+ Remove warnings for the coordinate conflict.

* Some clean up. Fix error in test_reindex_warning

* Enable vindex for PandasIndexAdapter.

* Add deprecation warning for isel_points

* Add a sanity check for boolean vectorized indexing.

* Modify tests to take care of the sanity check related to boolean array indexing.

* Another follow up

* pep8

* Clean up sanity checks in broadcast_indexers

* Fix unintended rename

* indexing.rst edits

* remove note about conflicts for now

* Apply coordinate conflict rule.

* Python 2 support

* Add tests for mindex selection.

* Drop coordinate of itself.

* Clean up the coordinate dropping logic.

* A small bug fix in coordinate dropping logic

* Fixes based on jhamman's comments.

* Improve test for warning.

* Remove unused assert sentence.

* Simplify rules for indexing conflicts

* Better error-message for multiindex vectorized-selection.

Author: fujiisoup

doc/api.rst

@@ -105,8 +105,6 @@ Indexing
    Dataset.loc
    Dataset.isel
    Dataset.sel
-   Dataset.isel_points
-   Dataset.sel_points
    Dataset.squeeze
    Dataset.reindex
    Dataset.reindex_like
@@ -247,8 +245,6 @@ Indexing
    DataArray.loc
    DataArray.isel
    DataArray.sel
-   DataArray.isel_points
-   DataArray.sel_points
    DataArray.squeeze
    DataArray.reindex
    DataArray.reindex_like