squlearn.qnn.lowlevel_qnn_qiskit.Expec
- class squlearn.qnn.lowlevel_qnn_qiskit.Expec(wave_function: str | tuple | ParameterVectorElement, observable: str, label: str = '')
Data structure that holds the set-up of derivative of the expectation value.
- Parameters:
wave_function (Union[str, tuple, ParameterVectorElement]) – Describes the wave function or its derivative. If tuple or ParameterVectorElement the differentiation with respect to the parameters in the tuple or with respect to the ParameterVectorElement is considered
observable (str) – String for the expectation value observable (
"O","OO","dop","dopdop","var").label (str) – Label that is used for displaying or in the value dict of the QNN class.
- classmethod from_parameter(val: ParameterVectorElement, operator: str = 'O')
Creates an Expec object from an inputted parameter
- Parameters:
val (ParameterVectorElement) – Parameter that is used in the differentiation.
operator (str) – String for the operator, default=’O’.
- Returns
Associated Expec object
- classmethod from_parameter_vector(val: ParameterVectorElement, operator: str = 'O')
Creates an Expec object from an inputted parameter
- Parameters:
val (ParameterVectorElement) – Parameter that is used in the differentiation.
operator (str) – String for the operator, default=’O’.
- Returns
Associated Expec object
- classmethod from_string(val: str)
Converts an input string to the Expec data structure.
- Parameters:
derivative (String that defines the expectation value)
- Returns:
Associated Expec object
- classmethod from_tuple(val: tuple, operator: str = 'O', label=None)
Creates an Expec object from an input tuple
- Parameters:
val (tuple) – Tuple for the differentiation of the wave function.
operator (str) – String for the operator, default=’O’.
- Returns
Associated Expec object