Symfit 0.5.2 offers a fantastic new feature: ODEModels now also accept parameter objects as initial values, allowing them to be optimized as well! Additionally it undoes some of the performance penalties that were accidentally introduced in 0.5.0-0.5.1, making it as fast again as the 0.4.x series.
ODEModels can now use parameters for their initial values, so these can be optimized during the fitting!
Hessian and jocobian models are now generated lazily to prevent slow model building.
The output of models was a namedtuple, which has a limit to the amount of arguments in older python versions. This has therefore been replaced by a custom tuple subclass called ModelOutput.