Pywr

New Features

- Added `LossLink` node. (960)
- Added `MultiThresholdIndexParameter`. (969)
- Added two recorders that fit a KDE to time-series of storage volumes. (970, 971)
- Added an optional tags dictionary to `Component` for storing user defined metadata. (968)

Bug Fixes

- Support loading "area" and "level" attributes as parameters correctly. (972)

Miscellaneous

- Added CI support for Python-3.9 on manylinux. (954)

New Features

- Add additional "activation function" parameters: `BinaryStepParameter`, `RectifierParameter` and `LogisticParameter`. (965)

New Features

- Refactor node loading into two stages to solve circular loading problems. (945)
- Add additional `get_all_xxx` methods to core nodes to allow fetching `min_flow`, `max_flow` and `cost`
values for all scenarios simultaneously. (958)

Miscellaneous

- Switch to using Openpyxl for reading and writing Excel files (see changes to Pandas v1.2). (959)
- Dropped support for Python 3.6 following lack of support in upstream libraries (NumPy and Pandas). (959)

New Features

- Add optional `exclude_months` to `AnnualCountIndexThresholdRecorder`. (950)
- Update load methods of interpolation parameters so that they accept `interp_kwargs`. (943)
- Allow `InterpolateVolumeParameter` to use external data. (926)
- Added `NumpyArrayNodeCostRecorder` to recorder a timeseries of a node's cost attribute. (932)
- Added `to_dataframe()` method to `AnnualCountIndexThresholdRecorder` and `AnnualTotalFlowRecorder`. (939)

Bug Fixes

- Fixed a bug with `RbfProfileParameter` where it did not pass `rbf_kwargs` to the RBF functions. (946)
- Fixes to save and draw graph functions to improve handling virtual and child nodes. (938)

Documentation

- Updated installation docs. (931)
- Add missing parameters (`FlowParameter` and `DiscountFactorParameter`) to API docs. (934)

Miscellaneous

- Migrate continuous integration system from Travis and Appveyor to Github Actions. (948, 951, 952, 953)
- Removed deprecated `PiecewiseLinearControlCurve`. (947)
- Apply some PEP8 compliance fixes. (929)
- Remove use of `basestring` which was only needed for Python 2. (928)

New Features

- Added `BisectionSearchModel` that performs a bisectional search on a single parameter instead of a
standard simulation. (915)
- Allow `AggregatedNode` factors to be time-varying using `Parameter`s. (919)
- Added `RollingVirtualStorage` node intended for modelling rolling licenses. (891)
- Added `SeasonalVirtualStorage` node intended for modelling licenses that apply for limited periods. (923)

Bug Fixes

- Ensure `RollingMeanFlowNodeRecorder`'s internal memory pointer is reset correctly. (893)
- Fix a bug where `AggregatedNode` would warn about small factors with any negative value. (921)
- Fixed `AggreagtedNode` initial volume being incorrectly calculated when its dependent nodes used a proportional
initial volume. (922)

Miscellaneous

- Added `NullSolver` that performs no allocation and is intended for debugging purposes. (924)
- Added a small tolerance for equality checking of fixed bounds in the GLPK solvers. (925)

New Features

- A change to the behaviour of Storage nodes with parameters for `max_volume`. Such nodes must
now have both `initial_volume` and `initial_volume_pc` specified. This allows using arbitrary parameters
for `max_volume` provided the initial condition is explicitly defined in absolute and percentage terms. (690)
- Added `DelayNode` and `FlowDelayParameter` to allow emulation of time-of-travel. (904)
- Added `DiscountFactorParameter`. (901)
- Added support for optimising days of the year in `RbfProfileParameter`. (908)
- Added `NumpyArrayDailyProfileParameterRecorder` for recording calculated annual profiles, and
refactored the internal calculations around day of the year. `Timestep` now includes properties
for `dayofyear_index`, `week_index` and `is_leap_year`. (903)
- Added error logging in `Model`'s `load`, `setup`, `reset` and `finish` methods. Handling of unknown
component types now raises a custom `TypeNotFoundError`. (896)

Miscellaneous

- Improvements to API documentation. (905)