pygsti.data.datasetconstruction.filter_dataset

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pygsti.data.datasetconstruction.filter_dataset#

filter_dataset(dataset, sectors_to_keep, sindices_to_keep=None, new_sectors=None, idle=((),), record_zero_counts=True, filtercircuits=True)#

Creates a DataSet that is the restriction of dataset to sectors_to_keep.

This function aggregates (sums) outcomes in dataset which differ only in sectors (usually qubits - see below) not in sectors_to_keep, and removes any operation labels which act specifically on sectors not in sectors_to_keep (e.g. an idle gate acting on all sectors because it’s .sslbls is None will not be removed).

Here “sectors” are state-space labels, present in the circuits of dataset. Each sector also corresponds to a particular character position within the outcomes labels of dataset. Thus, for this function to work, the outcome labels of dataset must all be 1-tuples whose sole element is an n-character string such that each character represents the outcome of a single sector. If the state-space labels are integers, then they can serve as both a label and an outcome-string position. The argument new_sectors may be given to rename the kept state-space labels in the returned DataSet’s circuits.

A typical case is when the state-space is that of n qubits, and the state space labels the integers 0 to n-1. As stated above, in this case there is no need to specify sindices_to_keep. One may want to “rebase” the indices to 0 in the returned data set using new_sectors (E.g. sectors_to_keep == [4,5,6] and new_sectors == [0,1,2]).

Parameters:

  • dataset (DataSet object) – The input DataSet whose data will be processed.

  • sectors_to_keep (list or tuple) – The state-space labels (strings or integers) of the “sectors” to keep in the returned DataSet.

  • sindices_to_keep (list or tuple, optional) – The 0-based indices of the labels in sectors_to_keep which give the positions of the corresponding letters in each outcome string (see above). If the state space labels are integers (labeling qubits) thath are also letter-positions, then this may be left as None. For example, if the outcome strings of dataset are ‘00’,’01’,’10’,and ‘11’ and the first position refers to qubit “Q1” and the second to qubit “Q2” (present in operation labels), then to extract just “Q2” data sectors_to_keep should be [“Q2”] and sindices_to_keep should be [1].

  • new_sectors (list or tuple, optional) – New sectors names to map the elements of sectors_to_keep onto in the output DataSet’s circuits. None means the labels are not renamed. This can be useful if, for instance, you want to run a 2-qubit protocol that expects the qubits to be labeled “0” and “1” on qubits “4” and “5” of a larger set. Simply set sectors_to_keep == [4,5] and new_sectors == [0,1].

  • idle (string or Label, optional) – The operation label to be used when there are no kept components of a “layer” (element) of a circuit.

  • record_zero_counts (bool, optional) – Whether zero-counts present in the original dataset are recorded (stored) in the returned (filtered) DataSet. If False, then such zero counts are ignored, except for potentially registering new outcome labels.

  • filtercircuits (bool, optional) – Whether or not to “filter” the circuits, by removing gates that act outside of the sectors_to_keep.

Returns:

filtered_dataset – The DataSet with outcomes and circuits filtered as described above.

Return type:

DataSet object

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