SaveExpectationValue
class SaveExpectationValue(operator, label='expectation_value', unnormalized=False, pershot=False, conditional=False)
Bases: qiskit.providers.aer.library.save_instructions.save_data.SaveAverageData
Save expectation value of an operator.
Instruction to save the expectation value of a Hermitian operator.
The expectation value of a Hermitian operator for a simulator in quantum state :math`rho`is given by .
Parameters
- operator (Pauli orSparsePauliOp orOperator) – a Hermitian operator.
- label (str) – the key for retrieving saved data from results.
- unnormalized (bool) – If True return save the unnormalized accumulated or conditional accumulated expectation value over all shot [Default: False].
- pershot (bool) – if True save a list of expectation values for each shot of the simulation rather than the average over all shots [Default: False].
- conditional (bool) – if True save the average or pershot data conditional on the current classical register values [Default: False].
Raises
ExtensionError – if the input operator is invalid or not Hermitian.
This instruction can be directly appended to a circuit using the save_expectation_value() circuit method.
Methods
add_decomposition
SaveExpectationValue.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
SaveExpectationValue.assemble()
Return the QasmQobjInstruction for the intructions.
broadcast_arguments
SaveExpectationValue.broadcast_arguments(qargs, cargs)
Validation of the arguments.
Parameters
- qargs (List) – List of quantum bit arguments.
- cargs (List) – List of classical bit arguments.
Yields
Tuple(List, List) – A tuple with single arguments.
Raises
CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.
c_if
SaveExpectationValue.c_if(classical, val)
Add classical condition on register or cbit classical and value val.
copy
SaveExpectationValue.copy(name=None)
Copy of the instruction.
Parameters
name (str) – name to be given to the copied circuit, if None then the name stays the same.
Returns
a copy of the current instruction, with the name
updated if it was provided
Return type
inverse
SaveExpectationValue.inverse()
Special case. Return self.
is_parameterized
SaveExpectationValue.is_parameterized()
Return True .IFF. instruction is parameterized else False
mirror
SaveExpectationValue.mirror()
DEPRECATED: use instruction.reverse_ops().
Returns
a new instruction with sub-instructions
reversed.
Return type
qasm
SaveExpectationValue.qasm()
Return a default OpenQASM string for the instruction.
Derived instructions may override this to print in a different format (e.g. measure q[0] -> c[0];).
repeat
SaveExpectationValue.repeat(n)
Creates an instruction with gate repeated n amount of times.
Parameters
n (int) – Number of times to repeat the instruction
Returns
Containing the definition.
Return type
Raises
CircuitError – If n < 1.
reverse_ops
SaveExpectationValue.reverse_ops()
For a composite instruction, reverse the order of sub-instructions.
This is done by recursively reversing all sub-instructions. It does not invert any gate.
Returns
a new instruction with
sub-instructions reversed.
Return type
soft_compare
SaveExpectationValue.soft_compare(other)
Soft comparison between gates. Their names, number of qubits, and classical bit numbers must match. The number of parameters must match. Each parameter is compared. If one is a ParameterExpression then it is not taken into account.
Parameters
other (instruction) – other instruction.
Returns
are self and other equal up to parameter expressions.
Return type
bool
validate_parameter
SaveExpectationValue.validate_parameter(parameter)
Instruction parameters has no validation or normalization.
Attributes
decompositions
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
definition
Return definition in terms of other basic gates.
duration
Get the duration.
label
Return instruction label
Return type
str
params
return instruction params.
unit
Get the time unit of duration.