Phiflow

**New features**

- Add 1D support for u_net (TensorFlow only)
- Bug fixes and minor additions

Pull request 20

The branch 1.5 will be kept as stable / LTS for Φ-Flow 1

**New features**:
- Consistent floating point precision using `math.set_precision`
- MacCormack advection scheme
- Advanced demo scripts: `rotating_bar.py`, `vortex_fit.py`
- Basic implementation of Broyden's method for root finding
- Lots of convenience updates: `CenteredGrid.sample(function)`, `Domain.dx`, `general_grid_sample_nd`, `interpolate`

**Breaking changes**:
- Finite difference in `gradient` now uses central difference by default
- `Noise` now only has a single channel unless otherwise specified

Pull request 18

This is the last major update of the Φ_Flow 1.x series.

New features:
- TensorFlow: Seamless TensorFlow data pipeline integration, standard U-net architecture in `phi.tf.standard_networks`, CUDA resampling operator
- Improved support for point clouds and sampled fields (`SampledField`), RK4 advection
- Symbolic field math, `Noise` field to replace `math.randfreq()`
- Support for `STICKY` / `NO_SLIP` domain boundaries and moving/rotating obstacles
- Web interface: Quad view, improved color maps and more configuration settings, configurable axis order using `physics_config.x_first()`

Breaking changes:
- Change in `math.resample()` for `'constant'` boundaries. This affects only values sampled close to the boundary.
- Inflows now use antialiased geometry by default.
- (minor) Removed keyword arguments from `Field.at()` and `Field.sample_at()`.
- (minor) `Scene.copy_calling_script()` now has different keyword arguments.
- (minor) `GeometryMask` only holds one `Geometry` and behaves in line with `AnalyticField`.
- (minor) `math.resample()`: No longer accepts boundary `'zero'` as an alias for `'constant'`.

Deprecations:
- `load_state()`: Use `build_graph_input()` instead.
- `buoyancy()`: Use `density * -gravity * factor` in conjunction with `Field.at()` instead.
- `StaggeredGrid.from_scalar()`: Use `Field.at()` instead.
- `world.add_all()`: Use `world.add()` instead.
- `Dataset.add(), Dataset.remove()`: Mutable datasets are not supported.
- `Geometry.value_at()`: Use `Geometry.lies_inside()` instead.
- `union_mask()`: Use `mask(union())` instead.

This is the last official version with Python 2 and Python 3 support.

Version Highlights:
- Periodic pressure solve
- Improved structs: `content_type`, global item context, batched structs

Breaking Changes:
- (minor) Removed `item_condition` argument from `placeholder()`. Use the context item condition instead.
- (minor) `CenteredGrid.dtype` now returns a `CenteredGrid`. Same for `StaggeredGrid`.
- (minor) Passing `item_condition=None` anywhere now uses the context item condition. Use `item_condition=ALL_ITEMS` to iterate over all items.
- (minor) `StructBackend` now validates returned values by default. Replace it with `StructBackend(target_content_type=struct.INVALID)` to revert to old behavior.

Deprecations:
- `math.types`: Use `Struct.dtype` instead.
- `StateCollection.default_physics`
- `struct.unsafe()`: Set `content_type` to non-data instead.

Pull request https://github.com/tum-pbs/PhiFlow/pull/10

Version Highlights:
- Experimental support for PyTorch oprations
- Add struct traits
- Add ConstantVelocity

Breaking Changes: None

Deprecations:
- `TFApp`: Use `LearningApp` instead
- `CollectiveState`: Use `StateCollection` instead
- `Fan`: Use `Accelerator` instead

Pull request https://github.com/tum-pbs/PhiFlow/pull/5

Version Highlights:
- **GUI-2.0**: Improved web interface with multiple pages and experimental 3D WebGL renderer
- **Documentation**: Google Colab notebooks and better demo descriptions

Breaking Changes: None

Deprecations:
- `App.stride`: Use framerate instead of stride in App constructor
- `world.add`: Explicitly create a Physics object when adding a state to the world.

Pull request https://github.com/tum-pbs/PhiFlow/pull/2