TODO to support sensitivity studies

[sjdaines]

Will also need changes to PALEOmodel

This will require three groups of changes:

• [x] Reaction parameters (Addressed by https://github.com/PALEOtoolkit/PALEOboxes.jl/pull/118)

  • define a subset of parameters set from the SciML p vector that override values in yaml file.
  • changes to dispatch to merge in modified parameters during dispatch
  • some changes to PALEOmodel to aggregate these into a Vector and calculate Jacobians etc

• [ ] Constant Variables (currently initialised via attributes)

  • provide some way of defining which constant variables are considered modifiable for sensitivity studies
  • a method to change values in all data array sets in modeldata (when AD hence additional data arrays in use)
  • might be easiest to provide a new reaction that defines a non-constant variable with value set from a parameter, so that machinery can be reused?

• [ ] Initial values for state variables

  • probably needs changes to PALEOmodel to make it convenient to change these