Change in the driver output type

[gilrrei]

Change in driver run return type

With #241, we changed the output type of the driver from a tuple expecting result, gradient to a dictionary {"result": result, "gradient":gradient}

Does it affect me?

If you don't use data processors, so you don't extract data from your simulation results, you don't need to change anything. 🙏

If you have a custom driver (with a dataprocessor), i.e., not Jobscript, Mpi or Fourc, maybe yes. Otherwise, everything still works :)

What do I have to change in my custom driver?

If your the _get_results method of your driver returns the tuple result, gradient change it to {"result": result, "gradient":gradient} (You can omit the gradient if it's None). If you avoid this function altogether, do this change in the run method of your custom driver.

Why the change?

tl;dr move towards general data passing without the need for change base classes etc.

• Remove the need to pass gradient if no gradient is required
• Move towards allowing to pass arbitrary data upstream (not possible yet) by attaching them with a name, for example, displacements and stresses, hessian, simulation_times, etc. Since most iterators expect the result keys result and maybe gradient, only these are used. The goal is that this additional data is also written into the metadata file of each job (not the case yet)
• The return signature of the drivers is now the same as the ones from the model class :)