qiskit.providers.aer.library.SaveExpectationValueVariance¶
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class
SaveExpectationValueVariance(operator, label='expectation_value_variance', unnormalized=False, pershot=False, conditional=False)[source]¶ 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 \(H\) for a simulator in quantum state :math`rho`is given by \(\langle H\rangle = \mbox{Tr}[H.\rho]\). The variance is given by \(\sigma^2 = \langle H^2 \rangle - \langle H \rangle>^2\).
- Parameters
operator (Pauli or SparsePauliOp or Operator) – 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.
Note
This instruction can be directly appended to a circuit using the
save_expectation_value()circuit method.-
__init__(operator, label='expectation_value_variance', unnormalized=False, pershot=False, conditional=False)[source]¶ Instruction to save the expectation value and variance of a Hermitian operator.
The expectation value of a Hermitian operator \(H\) for a simulator in quantum state :math`rho`is given by \(\langle H\rangle = \mbox{Tr}[H.\rho]\). The variance is given by \(\sigma^2 = \langle H^2 \rangle - \langle H \rangle>^2\).
- Parameters
operator (Pauli or SparsePauliOp or Operator) – 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.
Note
This instruction can be directly appended to a circuit using the
save_expectation_value()circuit method.
Methods
__init__(operator[, label, unnormalized, …])Instruction to save the expectation value and variance of a Hermitian operator.
add_decomposition(decomposition)Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble()Return the QasmQobjInstruction for the intructions.
broadcast_arguments(qargs, cargs)Validation of the arguments.
c_if(classical, val)Add classical condition on register classical and value val.
copy([name])Copy of the instruction.
inverse()Special case.
Return True .IFF.
mirror()DEPRECATED: use instruction.reverse_ops().
qasm()Return a default OpenQASM string for the instruction.
repeat(n)Creates an instruction with gate repeated n amount of times.
For a composite instruction, reverse the order of sub-instructions.
soft_compare(other)Soft comparison between gates.
validate_parameter(parameter)Instruction parameters has no validation or normalization.
Attributes
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
Return definition in terms of other basic gates.
Get the duration.
return instruction params.
Get the time unit of duration.
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add_decomposition(decomposition)¶ Add a decomposition of the instruction to the SessionEquivalenceLibrary.
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assemble()¶ Return the QasmQobjInstruction for the intructions.
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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.
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c_if(classical, val)¶ Add classical condition on register classical and value val.
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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
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property
decompositions¶ Get the decompositions of the instruction from the SessionEquivalenceLibrary.
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property
definition¶ Return definition in terms of other basic gates.
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property
duration¶ Get the duration.
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inverse()¶ Special case. Return self.
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is_parameterized()¶ Return True .IFF. instruction is parameterized else False
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mirror()¶ DEPRECATED: use instruction.reverse_ops().
- Returns
- a new instruction with sub-instructions
reversed.
- Return type
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property
params¶ return instruction params.
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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];).
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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.
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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
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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
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property
unit¶ Get the time unit of duration.
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validate_parameter(parameter)¶ Instruction parameters has no validation or normalization.