sf.compilers.Passive¶
-
class
Passive
[source]¶ Bases:
strawberryfields.compilers.compiler.Compiler
Compiler to write a sequence of passive operations as a single passive operation
This compiler checks whether the circuit can be implemented as a sequence of passive operations. If so, it arranges them in a single matrix, T. It then returns an PassiveChannel operation which can act this transformation.
This compiler can be accessed by calling
Program.compile()
with ‘passive’ specified.Example:
Consider the following Strawberry Fields program, compiled using the ‘passive’ compiler:
from strawberryfields.ops import BSgate, LossChannel, Rgate import strawberryfields as sf circuit = sf.Program(2) with circuit.context as q: Rgate(np.pi) | q[0] BSgate(0.25 * np.pi, 0) | (q[0], q[1]) LossChannel(0.9) | q[1] compiled_circuit = circuit.compile(compiler="passive")
We can now print the compiled circuit, consisting a single
PassiveChannel
:>>> compiled_circuit.print() PassiveChannel([[-0.7071+8.6596e-17j -0.7071+0.0000e+00j] [-0.6708+8.2152e-17j 0.6708+0.0000e+00j]]) | (q[0], q[1])
Attributes
A rigid circuit template that defines this circuit specification.
The allowed circuit topologies or connectivity of the class, modelled as a directed acyclic graph.
-
circuit
¶ A rigid circuit template that defines this circuit specification.
If arbitrary topologies are allowed in the circuit class, this function will simply return
None
.If a backend device expects a specific template for the received Blackbird script, this method will return the serialized Blackbird circuit in string form.
- Returns
Blackbird circuit or template representing the circuit
- Return type
Union[str, None]
-
decompositions
= {}¶
-
graph
¶ The allowed circuit topologies or connectivity of the class, modelled as a directed acyclic graph.
This property is optional; if arbitrary topologies are allowed in the circuit class, this will simply return
None
.- Returns
a directed acyclic graph
- Return type
networkx.DiGraph
-
interactive
= True¶
-
primitives
= {'All', 'BSgate', 'Interferometer', 'LossChannel', 'MZgate', 'PassiveChannel', 'Rgate', '_Delete', '_New_modes', 'sMZgate'}¶
-
short_name
= 'passive'¶
Methods
add_loss
(program, device)Adds realistic loss to circuit.
compile
(seq, registers)Try to arrange a passive circuit into a single multimode passive operation
decompose
(seq)Recursively decompose all gates in a given sequence, as allowed by the circuit specification.
init_circuit
(layout)Sets the circuit in the compiler class.
Resets the
circuit
andgraph
class attributes.update_params
(program, device)Updates and checks parameters in the program circuit.
-
add_loss
(program, device)¶ Adds realistic loss to circuit.
Child classes which are hardware compilers should override this method with device specific loss added to the circuit.
-
compile
(seq, registers)[source]¶ Try to arrange a passive circuit into a single multimode passive operation
This method checks whether the circuit can be implemented as a sequence of passive gates. If the answer is yes it arranges them into a single operation.
- Parameters
seq (Sequence[Command]) – passive quantum circuit to modify
registers (Sequence[RegRefs]) – quantum registers
- Returns
compiled circuit
- Return type
List[Command]
- Raises
CircuitError – the circuit does not correspond to a passive unitary
-
decompose
(seq)¶ Recursively decompose all gates in a given sequence, as allowed by the circuit specification.
This method follows the directives defined in the
primitives
anddecompositions
class attributes to determine whether a command should be decomposed.The order of precedence to determine whether decomposition should be applied is as follows.
First, we check if the operation is in
decompositions
. If not, decomposition is skipped, and the operation is applied as a primitive (if supported by theCompiler
).Next, we check if (a) the operation supports decomposition, and (b) if the user has explicitly requested no decomposition.
If both (a) and (b) are true, the operation is applied as a primitive (if supported by the
Compiler
).Otherwise, we attempt to decompose the operation by calling
decompose()
recursively.
- Parameters
list[strawberryfields.program_utils.Command] – list of commands to be decomposed
- Returns
list of compiled commands for the circuit specification
- Return type
-
classmethod
init_circuit
(layout)¶ Sets the circuit in the compiler class.
- Parameters
layout (str) – the circuit layout for the target device
- Return type
None
-
classmethod
reset_circuit
()¶ Resets the
circuit
andgraph
class attributes.- Return type
None
-
update_params
(program, device)¶ Updates and checks parameters in the program circuit.
Child classes can override this method with compiler specific logic. If no parameters need to be updated, and are separately checked, this method should not be overridden and be left empty.
- Parameters
program (Program) – Program containing the circuit and gate parameters
device (DeviceSpec) – device specification containing the valid parameter values
- Return type
None
-