pygsti.tools.errgenproptools.zassenhaus_formula_numerical

zassenhaus_formula_numerical(errorgen_groups, error_propagator, zassenhaus_order=1)

Function for numerically computing the nth-order Zassenhaus formula for a set of error generators. Please see https://en.wikipedia.org/wiki/Baker%E2%80%93Campbell%E2%80%93Hausdorff_formula#Zassenhaus_formula for more information on this approximation.

Due to the numerical nature of this implementation it is not meant for efficient computation and primarily supports testing.

Parameters:

• errorgen_groups (list of dicts) – List of dictionaries of the error generator coefficients and rates for a group of error generators corresponding to each of the operators in the sum to perform Zassenhaus with respect to. The error generator coefficients are represented using LocalStimErrorgenLabel.

• zassenhaus_order (int, optional (default 1)) – Order of the Zassenahaus formula to compute, currently supports up to second order.

• error_propagator (ErrorGeneratorPropagator)

Returns:

zassenhaus_formula_arrays – A list of numpy arrays, each corresponding to one of the operators which is exponentiated in the product as output by the Zassenhaus formula.

Return type:

list of numpy.ndarrays