SetDensityMatrix#
- class SetDensityMatrix(state)[source]#
Bases:
Instruction
Set density matrix state of the simulator
Create new instruction to set the density matrix state of the simulator.
- Parameters:
state (DensityMatrix) – a density matrix.
- Raises:
ValueError – if the input density matrix is not valid.
Note
This set instruction must always be performed on the full width of qubits in a circuit, otherwise an exception will be raised during simulation.
Attributes
- base_class#
Get the base class of this instruction. This is guaranteed to be in the inheritance tree of
self
.The “base class” of an instruction is the lowest class in its inheritance tree that the object should be considered entirely compatible with for _all_ circuit applications. This typically means that the subclass is defined purely to offer some sort of programmer convenience over the base class, and the base class is the “true” class for a behavioural perspective. In particular, you should not override
base_class
if you are defining a custom version of an instruction that will be implemented differently by hardware, such as an alternative measurement strategy, or a version of a parametrised gate with a particular set of parameters for the purposes of distinguishing it in aTarget
from the full parametrised gate.This is often exactly equivalent to
type(obj)
, except in the case of singleton instances of standard-library instructions. These singleton instances are special subclasses of their base class, and this property will return that base. For example:>>> isinstance(XGate(), XGate) True >>> type(XGate()) is XGate False >>> XGate().base_class is XGate True
In general, you should not rely on the precise class of an instruction; within a given circuit, it is expected that
Instruction.name
should be a more suitable discriminator in most situations.
- condition#
The classical condition on the instruction.
- condition_bits#
Get Clbits in condition.
- 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
- mutable#
Is this instance is a mutable unique instance or not.
If this attribute is
False
the gate instance is a shared singleton and is not mutable.
- name#
Return the name.
- num_clbits#
Return the number of clbits.
- num_qubits#
Return the number of qubits.
- params#
The parameters of this
Instruction
. Ideally these will be gate angles.
- unit#
Get the time unit of duration.
Methods
- add_decomposition(decomposition)[source]#
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
- broadcast_arguments(qargs, cargs)[source]#
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(classical, val)[source]#
Set a classical equality condition on this instruction between the register or cbit
classical
and valueval
.Note
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(name=None)[source]#
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(annotated: bool = False)[source]#
Invert this instruction.
If annotated is False, the inverse instruction is implemented as a fresh instruction with the recursively inverted definition.
If annotated is True, the inverse instruction is implemented as
AnnotatedOperation
, and corresponds to the given instruction annotated with the “inverse modifier”.Special instructions inheriting from Instruction can implement their own inverse (e.g. T and Tdg, Barrier, etc.) In particular, they can choose how to handle the argument
annotated
which may include ignoring it and always returning a concrete gate class if the inverse is defined as a standard gate.- Parameters:
annotated – if set to True the output inverse gate will be returned as
AnnotatedOperation
.- Returns:
The inverse operation.
- Raises:
CircuitError – if the instruction is not composite and an inverse has not been implemented for it.
- is_parameterized()[source]#
Return whether the
Instruction
contains compile-time parameters.
- repeat(n)[source]#
Creates an instruction with
self
repeated :math`n` times.If this operation has a conditional, the output instruction will have the same conditional and the inner repeated operations will be unconditional; instructions within a compound definition cannot be conditioned on registers within Qiskit’s data model. This means that it is not valid to apply a repeated instruction to a clbit that it both writes to and reads from in its condition.
- Parameters:
n (int) – Number of times to repeat the instruction
- Returns:
Containing the definition.
- Return type:
- Raises:
CircuitError – If n < 1.
- reverse_ops()[source]#
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(other: Instruction) bool [source]#
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