Both keywords refer to the same action which fulfills the same task: to sweep over some parameter, to compute all the detector outputs, to return a solution object with its result, and finally to reset all the values it has changed during the sweep.

The xaxis is used in KatScript command. It can be parsed together with other optical elements of the model or separately by itself in the run function of the model:

The xaxis KatScript command is associated with a similarly named class in finesse.analysis.actions: Xaxis. To use this action, first we need to import it and then to use it while running the model:

Notice the different use of quotation marks. The results are equivalent. The same correspondence can be found for other actions.