SaveExpectationValueVariance
class SaveExpectationValueVariance(operator, label='expectation_value_variance', unnormalized=False, pershot=False, conditional=False)
Bases: qiskit.providers.aer.library.save_instructions.save_data.SaveAverageData
Save expectation value and variance of an operator.
Instruction to save the expectation value and variance of a Hermitian operator.
The expectation value of a Hermitian operator for a simulator in quantum state :math`rho`is given by . The variance 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
SaveExpectationValueVariance.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
SaveExpectationValueVariance.assemble()
Return the QasmQobjInstruction for the intructions.
broadcast_arguments
SaveExpectationValueVariance.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
SaveExpectationValueVariance.c_if(classical, val)
Set a classical equality condition on this instruction between the register or cbit classical and value val.
This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.
copy
SaveExpectationValueVariance.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
SaveExpectationValueVariance.inverse()
Special case. Return self.
is_parameterized
SaveExpectationValueVariance.is_parameterized()
Return True .IFF. instruction is parameterized else False
qasm
SaveExpectationValueVariance.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
SaveExpectationValueVariance.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
SaveExpectationValueVariance.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
SaveExpectationValueVariance.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
SaveExpectationValueVariance.validate_parameter(parameter)
Instruction parameters has no validation or normalization.
Attributes
condition_bits
Get Clbits in condition.
Return type
List[Clbit]
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
name
Return the name.
num_clbits
Return the number of clbits.
num_qubits
Return the number of qubits.
params
return instruction params.
unit
Get the time unit of duration.