Robert Payton Kelly;
John King Gamble;
Adds a number of important updates and bug fixes, including:
fixes Windows-specific problems related to 32- vs 64-bit integers.
adds tools to estimating the wall time needed to execute an experiment design on a quantum processor.
fixes issues with extras.interpygate so that germ selection works and the number of gauge parameters can be specified manually.
adds "pad_1Q" implicit idle mode, which pads empty space in a circuit with 1-qubit idle operations.
adds SPAM and instrument elements to processor specifications.
adds QuditProcessorSpec object, so that processors containing multiple qudits can be readily modeled.
fixes bugs and adds functionality to first-order-gauge-invariant (FOGI) analysis routines.
improves circuit simulation performance when using operation factories (e.g., for modeling continuously parameterized gates)
revamps elementary error generator functionality to closely match arXiv:2103.01928, where there are H, S, C, and A type elementary generators.
default gauge optimization workflow changed for Lindblad-constrained models: now these models are converted to TP and gauge optimized over the entire TP gauge group (unitary group optimization was seen to be problematic for Lindblad-constrained models).
fixes a bug in Hessian projection that affects (and corrects) error bar computation.