# BooleanExpression#

class qiskit.circuit.classicalfunction.BooleanExpression(expression, name=None, var_order=None)[source]#

Bases: `ClassicalElement`

The Boolean Expression gate.

Parameters:
• expression (str) â€“ The logical expression string.

• name (str) â€“ Optional. Instruction gate name. Otherwise part of the expression is going to be used.

• var_order (list) â€“ A list with the order in which variables will be created. (default: by appearance)

Attributes

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

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.

Methods

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble()#

Assemble a QasmQobjInstruction

Validation and handling of the arguments and its relationship.

For example, `cx([q[0],q[1]], q[2])` means `cx(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]], []
```

• 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) â€“ List of quantum bit arguments.

• cargs (list) â€“ List of classical bit arguments.

Returns:

A tuple with single arguments.

Raises:

CircuitError â€“ If the input is not valid. For example, the number of arguments does not match the gate expectation.

Return type:
c_if(classical, val)#

Set a classical equality condition on this instruction between the register or cbit `classical` and value `val`.

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.

control(num_ctrl_qubits=1, label=None, ctrl_state=None)#

Return controlled version of gate. See `ControlledGate` for usage.

Parameters:
• num_ctrl_qubits (int) â€“ number of controls to add to gate (default: `1`)

• label (str | None) â€“ optional gate label

• ctrl_state (int | str | None) â€“ The control state in decimal or as a bitstring (e.g. `'111'`). If `None`, use `2**num_ctrl_qubits-1`.

Returns:

Controlled version of gate. This default algorithm uses `num_ctrl_qubits-1` ancilla qubits so returns a gate of size `num_qubits + 2*num_ctrl_qubits - 1`.

Return type:

qiskit.circuit.ControlledGate

Raises:

QiskitError â€“ unrecognized mode or invalid ctrl_state

copy(name=None)#

Copy of the instruction.

Parameters:

name (str) â€“ 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:

qiskit.circuit.Instruction

classmethod from_dimacs_file(filename)[source]#

Create a BooleanExpression from the string in the DIMACS format. :param filename: A file in DIMACS format.

Returns:

A gate for the input string

Return type:

BooleanExpression

Raises:

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:

qiskit.circuit.Instruction

Raises:

CircuitError â€“ 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

power(exponent)#

Creates a unitary gate as gate^exponent.

Parameters:

exponent (float) â€“ Gate^exponent

Returns:

To which to_matrix is self.to_matrix^exponent.

Return type:

qiskit.extensions.UnitaryGate

Raises:

CircuitError â€“ 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];`).

Deprecated since version 0.25.0: The method `qiskit.circuit.instruction.Instruction.qasm()` is deprecated as of qiskit-terra 0.25.0. It will be removed no earlier than 3 months after the release date. Correct exporting to OpenQASM 2 is the responsibility of a larger exporter; it cannot safely be done on an object-by-object basis without context. No replacement will be provided, because the premise is wrong.

repeat(n)#

Creates an instruction with gate repeated n amount of times.

Parameters:

n (int) â€“ Number of times to repeat the instruction

Returns:

Containing the definition.

Return type:

qiskit.circuit.Instruction

Raises:

CircuitError â€“ If n < 1.

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:

qiskit.circuit.Instruction

simulate(bitstring)[source]#

Evaluate the expression on a bitstring.

This evaluation is done classically.

Parameters:

bitstring (str) â€“ The bitstring for which to evaluate.

Returns:

result of the evaluation.

Return type:

bool

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) â€“ other instruction.

Returns:

are self and other equal up to parameter expressions.

Return type:

bool

synth(registerless=True, synthesizer=None)[source]#

Synthesis the logic network into a `QuantumCircuit`.

Parameters:
• registerless (bool) â€“ Default `True`. If `False` uses the parameter names to create registers with those names. Otherwise, creates a circuit with a flat quantum register.

• synthesizer (Callable[[BooleanExpression], QuantumCircuit] | None) â€“ A callable that takes self and returns a Tweedledum circuit.

Returns:

A circuit implementing the logic network.

Return type:

QuantumCircuit

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 â€“ If a Gate subclass does not implement this method an exception will be raised when this base class method is called.

validate_parameter(parameter)#

Gate parameters should be int, float, or ParameterExpression