qiskit.circuit.library.RCCXGate¶

class
RCCXGate
(label=None)[source]¶ The simplified Toffoli gate, also referred to as Margolus gate.
The simplified Toffoli gate implements the Toffoli gate up to relative phases. This implementation requires three CX gates which is the minimal amount possible, as shown in https://arxiv.org/abs/quantph/0312225. Note, that the simplified Toffoli is not equivalent to the Toffoli. But can be used in places where the Toffoli gate is uncomputed again.
This concrete implementation is from https://arxiv.org/abs/1508.03273, the dashed box of Fig. 3.
Create a new simplified CCX gate.
Methods
__init__
([label])Create a new simplified CCX gate.
add_decomposition
(decomposition)Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
()Assemble a QasmQobjInstruction
broadcast_arguments
(qargs, cargs)Validation and handling of the arguments and its relationship.
c_if
(classical, val)Add classical condition on register or cbit classical and value val.
control
([num_ctrl_qubits, label, ctrl_state])Return controlled version of gate.
copy
([name])Copy of the instruction.
inverse
()Invert this instruction.
Return True .IFF.
mirror
()DEPRECATED: use instruction.reverse_ops().
power
(exponent)Creates a unitary gate as gate^exponent.
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 subinstructions.
soft_compare
(other)Soft comparison between gates.
Return a Numpy.array for the gate unitary matrix.
validate_parameter
(parameter)Gate parameters should be int, float, or ParameterExpression
Attributes
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
Return definition in terms of other basic gates.
Get the duration.
Return instruction label
return instruction params.
Get the time unit of duration.

add_decomposition
(decomposition)¶ Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble
()¶ Assemble a QasmQobjInstruction

broadcast_arguments
(qargs, cargs)¶ Validation and handling of the arguments and its relationship.
For example,
cx([q[0],q[1]], q[2])
meanscx(q[0], q[2]); cx(q[1], q[2])
. This method yields the arguments in the right grouping. In the given example:in: [[q[0],q[1]], q[2]],[] outs: [q[0], q[2]], [] [q[1], q[2]], []
The general broadcasting rules are:
If len(qargs) == 1:
[q[0], q[1]] > [q[0]],[q[1]]
If len(qargs) == 2:
[[q[0], q[1]], [r[0], r[1]]] > [q[0], r[0]], [q[1], r[1]] [[q[0]], [r[0], r[1]]] > [q[0], r[0]], [q[0], r[1]] [[q[0], q[1]], [r[0]]] > [q[0], r[0]], [q[1], r[0]]
If len(qargs) >= 3:
[q[0], q[1]], [r[0], r[1]], ...] > [q[0], r[0], ...], [q[1], r[1], ...]
 Parameters
qargs (
List
) – List of quantum bit arguments.cargs (
List
) – List of classical bit arguments.
 Return type
Tuple
[List
,List
] Returns
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)¶ Add classical condition on register or cbit classical and value val.

control
(num_ctrl_qubits=1, label=None, ctrl_state=None)¶ Return controlled version of gate. See
ControlledGate
for usage. Parameters
num_ctrl_qubits (
Optional
[int
]) – number of controls to add to gate (default=1)label (
Optional
[str
]) – optional gate labelctrl_state (
Union
[int
,str
,None
]) – The control state in decimal or as a bitstring (e.g. ‘111’). If None, use 2**num_ctrl_qubits1.
 Returns
Controlled version of gate. This default algorithm uses num_ctrl_qubits1 ancillae qubits so returns a gate of size num_qubits + 2*num_ctrl_qubits  1.
 Return type
 Raises
QiskitError – unrecognized mode or invalid ctrl_state

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

property
decompositions
¶ Get the decompositions of the instruction from the SessionEquivalenceLibrary.

property
definition
¶ Return definition in terms of other basic gates.

property
duration
¶ Get the duration.

inverse
()¶ Invert this instruction.
If the instruction is composite (i.e. has a definition), then its definition will be recursively inverted.
Special instructions inheriting from Instruction can implement their own inverse (e.g. T and Tdg, Barrier, etc.)
 Returns
a fresh instruction for the inverse
 Return type
 Raises
CircuitError – if the instruction is not composite and an inverse has not been implemented for it.

is_parameterized
()¶ Return True .IFF. instruction is parameterized else False

property
label
¶ Return instruction label
 Return type
str

mirror
()¶ DEPRECATED: use instruction.reverse_ops().
 Returns
 a new instruction with subinstructions
reversed.
 Return type

property
params
¶ return instruction params.

power
(exponent)¶ Creates a unitary gate as gate^exponent.
 Parameters
exponent (float) – Gate^exponent
 Returns
To which to_matrix is self.to_matrix^exponent.
 Return type
 Raises
CircuitError – If Gate is not unitary

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
(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
()¶ For a composite instruction, reverse the order of subinstructions.
This is done by recursively reversing all subinstructions. It does not invert any gate.
 Returns
 a new instruction with
subinstructions reversed.
 Return type

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

to_matrix
()¶ Return a Numpy.array for the gate unitary matrix.
 Returns
if the Gate subclass has a matrix definition.
 Return type
np.ndarray
 Raises
CircuitError – If a Gate subclass does not implement this method an exception will be raised when this base class method is called.

property
unit
¶ Get the time unit of duration.

validate_parameter
(parameter)¶ Gate parameters should be int, float, or ParameterExpression
