pygsti.tools.rbtheory.transform_to_rb_gauge

pygsti.tools.rbtheory.transform_to_rb_gauge#

transform_to_rb_gauge(model, target_model, weights=None, mx_basis=None, eigenvector_weighting=1.0)#

Transforms a Model into the “RB gauge” (see the RB_gauge function).

This notion was introduced in Proctor et al Phys. Rev. Lett. 119, 130502 (2017). This gauge is a function of both the model and its target. These may be input in any gauge, for the purposes of obtaining “r = average model infidelity” between the output Model and target_model.

Parameters:

  • model (Model) – The RB model. This is not necessarily the set of physical primitives – it is the model randomly sampled over in the RB protocol (e.g., the Cliffords).

  • target_model (Model) – The target model corresponding to model. This function is not invariant under swapping model and target_model: this Model must be the target model, and should consistent of perfect gates.

  • weights (dict, optional) – If not None, a dictionary of floats, whereby the keys are the gates in model and the values are the unnormalized probabilities to apply each gate at each stage of the RB protocol. If not None, the values in weights must all be non-negative, and they must not all be zero. Because, when divided by their sum, they must be a valid probability distribution. If None, the weighting defaults to an equal weighting on all gates, as this is used in many RB protocols (e.g., Clifford RB). But, this weighting is flexible in the “direct RB” protocol.

  • mx_basis ({"std","gm","pp"}, optional) – The basis of the models. If None, the basis is obtained from the model.

  • eigenvector_weighting (float, optional) – Must be non-zero. A weighting on the eigenvector with eigenvalue that is the RB decay parameter, in the sum of this eigenvector and the eigenvector with eigenvalue of 1 that defines the returned matrix l_operator. The value of this factor does not change whether this l_operator transforms into a gauge in which r = AGsI, but it may impact on other properties of the gates in that gauge. It is irrelevant if the gates are unital.

Returns:

model_in_RB_gauge – The model model transformed into the “RB gauge”.

Return type:

Model