OptionalkeyThe home key of the plan. Every reference key moves by the interval from the reference's home tonic to this one, keeping its own variant. Defaults to the reference's home key; a key of another variant is rejected.
OptionalregisterThe melody range the plan's phrase registers are mapped onto. Defaults to the reference's melody range, moved by the nearest shift to the new key.
OptionalpreserveHow much of each dimension of the reference to keep; see PreserveWeights.
OptionalctxThe seed and algorithm version the plan records. A caller-supplied rng
is rejected: a plan has to carry its source as a seed to be reproducible.
OptionalbudgetUpper bound on the motif selection.
Options for deriveCompositionPlan.