Linear-operator

What's Changed

Documentation
* Add basic example notebook by Balandat in https://github.com/cornellius-gp/linear_operator/pull/17

New torch api compatibility
* Register torch.linalg.solve_triangular with LinearOperator by Balandat in https://github.com/cornellius-gp/linear_operator/pull/29
* Register torch.isclose by Balandat in https://github.com/cornellius-gp/linear_operator/pull/31
* Introduce reshape by Balandat in https://github.com/cornellius-gp/linear_operator/pull/32

Performance
* Performant Scaling of `BlockDiagLinearOperator` by `DiagLinearOperator` by SebastianAment in https://github.com/cornellius-gp/linear_operator/pull/14
* Edits to generic `add`, `BlockDiagLinearOperator`'s `matmul`, and documentation by SebastianAment in https://github.com/cornellius-gp/linear_operator/pull/10

Bug Fixes
* Fix linear operator mul torch.Tensor by dannyfriar in https://github.com/cornellius-gp/linear_operator/pull/35
* Update LO.__getitem__ to handle broadcasted tensor indices. by gpleiss in https://github.com/cornellius-gp/linear_operator/pull/26
* adding unsqueeze to initial_guess in linear_cg when appropriate by tvercaut in https://github.com/cornellius-gp/linear_operator/pull/22
* Removing `deepcopy` in `add` because of downstream failure in BoTorch by SebastianAment in https://github.com/cornellius-gp/linear_operator/pull/12
* Patches for `ConstantDiagLinearOperator._mul_constant` and `ConstantMulLinearOperator._getitem`. by j-wilson in https://github.com/cornellius-gp/linear_operator/pull/37

New Contributors
* wbeardall made their first contribution in https://github.com/cornellius-gp/linear_operator/pull/9
* tvercaut made their first contribution in https://github.com/cornellius-gp/linear_operator/pull/22
* karstenBehrendt made their first contribution in https://github.com/cornellius-gp/linear_operator/pull/36
* dannyfriar made their first contribution in https://github.com/cornellius-gp/linear_operator/pull/35
* j-wilson made their first contribution in https://github.com/cornellius-gp/linear_operator/pull/37

**Full Changelog**: https://github.com/cornellius-gp/linear_operator/compare/v0.1.1...v0.2.0

**Full Changelog**: https://github.com/cornellius-gp/linear_operator/compare/v0.1.0...v0.1.1

Welcome to LinearOperator!

This repo is in charge of what was previously known as `LazyTensor` in GPyTorch. It is currently a package that is predominantly used within GPyTorch, and assumes that the `LinearOperators` will be PSD kernel matrices. In the future, the goal is to make this a more generic implementation of LinearOperators that can be used in any number of applications.

What's new

For now, this implementation is very similar to what is currently in GPyTorch (v1.8.1). The only major difference is that `*LazyTensor` has been renamed to `*LinearOperator`.