Classes
class	qgd_SABRE

Functions
def	__init__ (self, quantum_circuit, topology, max_lookahead=4, max_E_size=20, W=0.5, alpha=0.9)
	Constructor of the class. More...

def	calculate_gate_depth (self, gate_idx, IDAG, resolved_gates)
	Calculates the number of predecessing unresolved gates for a gate. More...

def	check_dependencies (self, gate_idx, IDAG, resolved_gates)
	Checks if gate dependencies have been resolved. More...

def	Floyd_Warshall (self)
	Floyd_warshall algorithm to calculate distance matrix. More...

def	generate_DAG (self, circuit)
	generates DAG of input circuit More...

def	generate_E (self, F, DAG, IDAG, resolved_gates)
	Generates lookahead extended layer containing all upcoming two qubit gates. More...

def	generate_inverse_DAG (self, circuit)
	generates inverse DAG of input circuit More...

def	geneterate_possible_connections (self)
	generate list of possible connections based on inputted topology More...

def	get_initial_layer (self, circuit)
	generates initial layer of input circuit for more see at: https://arxiv.org/pdf/1809.02573 More...

def	get_inverse_pi (self, pi)
	returns inverse pi mapping physical qubits Q to virtual qubits q More...

def	get_mapped_circuit (self, circuit, init_pi, gate_order, flags, parameters)
	Returns mapped circuit on physical qubits Q with swaps included. More...

def	get_reverse_circuit (self, circuit)
	generates reverse circuit More...

def	H_basic (self, pi, q1, q2)
	basic cost function that returns distance of two virtual qubits q1 and q2 More...

def	Heuristic_search (self, F, pi, DAG, IDAG)
	Heuristic search to map circuit to topology based on initial mapping pi this is an implementation of Algorithm 1 as seen in: https://arxiv.org/pdf/1809.02573. More...

def	is_gate_possible (self, pi, q_target, q_control)
	checks if connection between two virtual qubits q_target and q_control is possible, if second return is 1 it means gate might need to be inverted (with H gates in the case of CNOT) More...

def	map_circuit (self, parameters=np.array([]), iter_num=1)
	Returns mapped circuit on physical qubits Q with swaps included. More...

def	obtain_SWAPS (self, F, pi, DAG)
	Get all possible swaps between all involved qubits in F F front layer containing unresolved gates. More...

def	update_pi (self, pi, SWAP)
	basic cost function that returns distance of two virtual qubits q1 and q2 More...

Variables
	alpha

	circuit_qbit_num

	D

	initial_circuit

	max_E_size

	max_lookahead

	neighbours

	pi

	qbit_num

	topology

	W

Function Documentation

◆ init()

def qgd_SABRE.__init__	(	self,
		quantum_circuit,
		topology,
		max_lookahead = `4`,
		max_E_size = `20`,
		W = `0.5`,
		alpha = `0.9`
	)

Constructor of the class.

Parameters

quantum_circuit	SQUANDER circuit to be mapped and routed
topology	target topology for circuit to be routed to
max_E_size	Maximum lookahead size for more see at: https://arxiv.org/pdf/1809.02573
W	lookahead cost function weight for more see at: https://arxiv.org/pdf/1809.02573

Definition at line 38 of file qgd_SABRE.py.

◆ calculate_gate_depth()

def qgd_SABRE.calculate_gate_depth	(	self,
		gate_idx,
		IDAG,
		resolved_gates
	)

Calculates the number of predecessing unresolved gates for a gate.

Parameters

gate_idx	gate to be calculated "distance for"
DAG	circuit DAG
resolved_gates	indicates whether gate at index is resolved or not
F	front layer

Definition at line 228 of file qgd_SABRE.py.

◆ check_dependencies()

def qgd_SABRE.check_dependencies	(	self,
		gate_idx,
		IDAG,
		resolved_gates
	)

Checks if gate dependencies have been resolved.

Parameters

gate_idx	gate to check
IDAG	inverse DAG of circuit
resolved_gates	indicates whether gate at index is resolved or not

Definition at line 246 of file qgd_SABRE.py.

◆ Floyd_Warshall()

def qgd_SABRE.Floyd_Warshall ( self )

Floyd_warshall algorithm to calculate distance matrix.

Definition at line 54 of file qgd_SABRE.py.

◆ generate_DAG()

def qgd_SABRE.generate_DAG	(	self,
		circuit
	)

generates DAG of input circuit

Parameters

cirucit Circuit to generate DAG of

Definition at line 95 of file qgd_SABRE.py.

◆ generate_E()

def qgd_SABRE.generate_E	(	self,
		F,
		DAG,
		IDAG,
		resolved_gates
	)

Generates lookahead extended layer containing all upcoming two qubit gates.

Parameters

F	front layer containing unresolved gates
DAG	dag to walk

Definition at line 199 of file qgd_SABRE.py.

◆ generate_inverse_DAG()

def qgd_SABRE.generate_inverse_DAG	(	self,
		circuit
	)

generates inverse DAG of input circuit

Parameters

cirucit Circuit to generate inverse DAG of

Definition at line 104 of file qgd_SABRE.py.

◆ geneterate_possible_connections()

def qgd_SABRE.geneterate_possible_connections ( self )

generate list of possible connections based on inputted topology

Definition at line 70 of file qgd_SABRE.py.

◆ get_initial_layer()

def qgd_SABRE.get_initial_layer	(	self,
		circuit
	)

generates initial layer of input circuit for more see at: https://arxiv.org/pdf/1809.02573

Parameters

cirucit Circuit to generate intial layer of

Definition at line 113 of file qgd_SABRE.py.

◆ get_inverse_pi()

def qgd_SABRE.get_inverse_pi	(	self,
		pi
	)

returns inverse pi mapping physical qubits Q to virtual qubits q

Parameters

pi	mapping between virtual qubits q and physical qubits Q

Definition at line 161 of file qgd_SABRE.py.

◆ get_mapped_circuit()

def qgd_SABRE.get_mapped_circuit	(	self,
		circuit,
		init_pi,
		gate_order,
		flags,
		parameters
	)

Returns mapped circuit on physical qubits Q with swaps included.

Parameters

circuit	circuit to be mapped
init_pi	intial mapping between virtual qubits q and physical qubits Q
gate_order	order of gates to be excecuted on physical hardware (swaps included)
flags	sign if flipping target and control in gate is necessary
parameters	parameters belonging to the initial circuit

Definition at line 339 of file qgd_SABRE.py.

◆ get_reverse_circuit()

def qgd_SABRE.get_reverse_circuit	(	self,
		circuit
	)

generates reverse circuit

Parameters

circuit Circuit to be reversed

Definition at line 84 of file qgd_SABRE.py.

◆ H_basic()

def qgd_SABRE.H_basic	(	self,
		pi,
		q1,
		q2
	)

basic cost function that returns distance of two virtual qubits q1 and q2

Parameters

pi	mapping between virtual qubits q and physical qubits Q
q1	virtual qubit that is the target of the gate
q2	virtual qubit that is the control of the gate

Definition at line 144 of file qgd_SABRE.py.

◆ Heuristic_search()

def qgd_SABRE.Heuristic_search	(	self,
		F,
		pi,
		DAG,
		IDAG
	)

Heuristic search to map circuit to topology based on initial mapping pi this is an implementation of Algorithm 1 as seen in: https://arxiv.org/pdf/1809.02573.

Parameters

F	front layer containing unresolved gates
pi	mapping between virtual qubits q and physical qubits Q
DAG	DAG of circuit
IDAG	inverse DAG of circuit

Definition at line 266 of file qgd_SABRE.py.

◆ is_gate_possible()

def qgd_SABRE.is_gate_possible	(	self,
		pi,
		q_target,
		q_control
	)

checks if connection between two virtual qubits q_target and q_control is possible, if second return is 1 it means gate might need to be inverted (with H gates in the case of CNOT)

Parameters

pi	mapping between virtual qubits q and physical qubits Q
q_target	virtual qubit that is the target of the gate
q_control	virtual qubit that is the control of the gate

Definition at line 126 of file qgd_SABRE.py.

◆ map_circuit()

def qgd_SABRE.map_circuit	(	self,
		parameters = `np.array([])`,
		iter_num = `1`
	)

Returns mapped circuit on physical qubits Q with swaps included.

Parameters

parameters	parameters belonging to initial circuit defined in init
iter_num	number of iterations to execute during reversal traversal to find optimal mapping, for more see at: https://arxiv.org/pdf/1809.02573

Definition at line 378 of file qgd_SABRE.py.

◆ obtain_SWAPS()

def qgd_SABRE.obtain_SWAPS	(	self,
		F,
		pi,
		DAG
	)

Get all possible swaps between all involved qubits in F F front layer containing unresolved gates.

Parameters

pi	mapping between virtual qubits q and physical qubits Q
DAG	DAG of circuit

Definition at line 173 of file qgd_SABRE.py.

◆ update_pi()

def qgd_SABRE.update_pi	(	self,
		pi,
		SWAP
	)

basic cost function that returns distance of two virtual qubits q1 and q2

Parameters

pi	mapping between virtual qubits q and physical qubits Q
SWAP	virtual qubits to be swapped

Definition at line 152 of file qgd_SABRE.py.

Variable Documentation

◆ alpha

qgd_SABRE.alpha

Definition at line 48 of file qgd_SABRE.py.

◆ circuit_qbit_num

qgd_SABRE.circuit_qbit_num

Definition at line 39 of file qgd_SABRE.py.

◆ D

qgd_SABRE.D

Definition at line 45 of file qgd_SABRE.py.

◆ initial_circuit

qgd_SABRE.initial_circuit

Definition at line 41 of file qgd_SABRE.py.

◆ max_E_size

qgd_SABRE.max_E_size

Definition at line 46 of file qgd_SABRE.py.

◆ max_lookahead

qgd_SABRE.max_lookahead

Definition at line 50 of file qgd_SABRE.py.

◆ neighbours

qgd_SABRE.neighbours

Definition at line 49 of file qgd_SABRE.py.

◆ pi

qgd_SABRE.pi

Definition at line 42 of file qgd_SABRE.py.

◆ qbit_num

qgd_SABRE.qbit_num

Definition at line 40 of file qgd_SABRE.py.

◆ topology

qgd_SABRE.topology

Definition at line 44 of file qgd_SABRE.py.

◆ W

qgd_SABRE.W

Definition at line 47 of file qgd_SABRE.py.

Classes

Functions

Variables

Function Documentation

◆ __init__()

◆ calculate_gate_depth()

◆ check_dependencies()

◆ Floyd_Warshall()

◆ generate_DAG()

◆ generate_E()

◆ generate_inverse_DAG()

◆ geneterate_possible_connections()

◆ get_initial_layer()

◆ get_inverse_pi()

◆ get_mapped_circuit()

◆ get_reverse_circuit()

◆ H_basic()

◆ Heuristic_search()

◆ is_gate_possible()

◆ map_circuit()

◆ obtain_SWAPS()

◆ update_pi()

Variable Documentation

◆ alpha

◆ circuit_qbit_num

◆ D

◆ initial_circuit

◆ max_E_size

◆ max_lookahead

◆ neighbours

◆ pi

◆ qbit_num

◆ topology

◆ W

◆ init()