pwc_pairs_to_arrays

The Boulder Opal Toolkits are currently in beta phase of development. Breaking changes may be introduced.

pwc_pairs_to_arrays(pwc)

Extract arrays with the durations and values representing a piecewise-constant function from a list of dictionaries with “value” and “duration” keys.

You can use this function to retrieve the durations and values of a PWC extracted from a Boulder Opal graph calculation.

Parameters:

pwc (list[...list[list[dict]]]) – A nested list of lists of … of list of dictionaries. The outer lists represent batches. The dictionaries in the innermost list must have “value” and “duration” keys, defining a PWC.

Returns:

np.ndarray – The durations of the PWC.
np.ndarray – The values of the PWC.
int – The number of batch dimensions.

See also

utils.pwc_arrays_to_pairs(): Perform the inverse conversion.

Examples

>>> pwc_example = [
             {'duration': 1.0, 'value': 3},
             {'duration': 0.5, 'value': -2},
             {'duration': 0.5, 'value': 4},
             ]
>>> qctrl.utils.pwc_pairs_to_arrays(pwc_example)
    (array([1., 0.5, 0.5]), array([3, -2, 4]), 0)

>>> pwc_example = [
            [{'duration': 1.0, 'value': 3},
             {'duration': 0.5, 'value': -2},
             {'duration': 0.5, 'value': 4}],
            [{'duration': 1.0, 'value': 2},
             {'duration': 0.5, 'value': 3},
             {'duration': 0.5, 'value': -1}]
             ]
>>> qctrl.utils.pwc_pairs_to_arrays(pwc_example)
    (array([1., 0.5, 0.5]),
     array([[3, -2, 4],
            [2,  3, -1]]),
     1)

Define a PWC from a graph calculation.

>>> graph.pwc(*qctrl.utils.pwc_pairs_to_arrays(result.output['signal']))
    <Pwc: name="pwc_#1", operation_name="pwc", value_shape=(), batch_shape=(4, 3)>