Adds AdamW optimiser

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Features
 
+- [#316](https://github.com/pybop-team/PyBOP/pull/316) - Adds Adam with weight decay (AdamW) optimiser, replaces pints.Adam implementation.
 - [#315](https://github.com/pybop-team/PyBOP/pull/315) - Updates __init__ structure to remove circular import issues and minimises dependancy imports across codebase for faster PyBOP module import. Adds type-hints to BaseModel and refactors rebuild parameter variables.
 - [#236](https://github.com/pybop-team/PyBOP/issues/236) - Restructures the optimiser classes, adds a new optimisation API through direct construction and keyword arguments, and fixes the setting of `max_iterations`, and `_minimising`. Introduces `pybop.BaseOptimiser`, `pybop.BasePintsOptimiser`, and `pybop.BaseSciPyOptimiser` classes.
 - [#321](https://github.com/pybop-team/PyBOP/pull/321) - Updates Prior classes with BaseClass, adds a `problem.sample_initial_conditions` method to improve stability of SciPy.Minimize optimiser.

benchmarks/benchmark_parameterisation.py

@@ -13,7 +13,7 @@ class BenchmarkParameterisation:
         [
             pybop.SciPyMinimize,
             pybop.SciPyDifferentialEvolution,
-            pybop.Adam,
+            pybop.AdamW,
             pybop.CMAES,
             pybop.GradientDescent,
             pybop.IRPropMin,

benchmarks/benchmark_track_parameterisation.py

@@ -13,7 +13,7 @@ class BenchmarkTrackParameterisation:
         [
             pybop.SciPyMinimize,
             pybop.SciPyDifferentialEvolution,
-            pybop.Adam,
+            pybop.AdamW,
             pybop.CMAES,
             pybop.GradientDescent,
             pybop.IRPropMin,