pygsti.tools.errgenproptools.bch_approximation

pygsti.tools.errgenproptools.bch_approximation#

bch_approximation(errgen_layer_1, errgen_layer_2, bch_order=1, truncation_threshold=1e-14)#

Apply the BCH approximation at the given order to combine the input dictionaries of error generator rates.

Parameters:

  • errgen_layer_1 (dict) – Dictionary of the error generator coefficients and rates for a circuit layer. The error generator coefficients are represented using LocalStimErrorgenLabel.

  • errgen_layer_2 (list of dicts) – See errgen_layer_1.

  • bch_order (int, optional (default 1)) – Order of the BCH approximation to use. Currently support for up to fifth order.

  • truncation_threshold (float, optional (default 1e-14)) – Threshold for which any error generators with magnitudes below this value are truncated.

Returns:

combined_errgen_layer – A dictionary with the same general structure as errgen_layer_1 and errgen_layer_2, but with the rates combined according to the selected order of the BCH approximation.

Return type:

dict