qat.lang.linking.Linker

class qat.lang.linking.Linker(gate_set=None, include_matrices=True, keep=None, link=None, submatrices_only=False, inline=False, include_locks=False)

The purpose of a linker is to crawl a circuit and attach implementations to gates. These implementations are specified via a GateSet object (more or less a collection of AbstractGate).

The main method of this class is the .link method.

The following example uses a linker to replace CNOT gates by H and CZ gates:

from qat.lang.AQASM import *
from qat.core.gate_set import GateSet
from qat.lang.linking.linker import Linker

prog = Program()
qbits = prog.qalloc(2)
CNOT(qbits)
circuit = prog.to_circ()

@build_gate('CNOT', [], arity=2)
def my_cnot_implementation():
    rout = QRoutine()
    wires = rout.new_wires(2)
    with rout.compute():
        H(wires[1])
    CSIGN(wires)
    rout.uncompute()
    return rout

# We initialize a Linker with an empty gate set since we want
# to override the default CNOT implementation
linker = Linker(gate_set=GateSet())
linker.add_signature(my_cnot_implementation)

print("Before linking:")
for op in circuit.iterate_simple():
    print(op)

linker.link(circuit)
print("After linking:")
for op in circuit.iterate_simple():
    print(op)

Before linking:
('CNOT', [], [0, 1])
After linking:
('H', [], [1])
('CSIGN', [], [0, 1])
('H', [], [1])
Parameters

  • gate_set (GateSet) – A gate set to start the linking with. Optional. Defaults to the default pyAQASM gate set.

  • include_matrices (bool, optional) – if set to True, matrices will be generated and included in the circuit. Defaults to True.

  • keep (list<str>) – if set to a list of gate names, these gates will be skipped by the linker. Default to None.

  • link (list) – a list of AbstractGate, GateSet, or python modules to pass to the linker.

  • submatrices_only (bool) – if set to True, only submatrices will be generated and included in the circuit. For instance a CTRL(Y) will only generate the matrix for Y, thus saving memory. Default to True.

  • inline (bool, optional) – if set to True, subcircuit implementations will be inlined in the main body of the circuit. This might increase the memory footprint of the circuit and linking cost. Default to False.

  • include_locks (bool, optional) – if set to False, removes all lock/release operators after the linking process. If set to True, these operators will remain. These operators are here for debug purpose only. Defaults to False.

add_signature(gate_signature)

Adds a gate signature to the current gate set of the Linker. This gate should not be present in the current gate set.

Parameters

gate_signature (GateSignature) – a gate signature

clear_gate_set(default_gates=True)

Resets the content of the internal gate set of the Linker.

Parameters

default_gates (bool) – If set to True, the default gate set of pyAQASM will be included in the fresh gate set. Optional. Defaults to True.

compile(batch, _specs)

Applies the linker to all the jobs in a batch.

Uses the internal gate set of the Linker to link gate implementations.

Warning

The linking happens in place (thus modifies the input circuit).

Parameters

circuit (qat.core.Circuit) – a quantum circuit

Uses the internal gate set of the Linker to instantiate the gates of a circuit.

Warning

The linking happens in place (thus modifies the input circuit).

Parameters

circuit (qat.core.Circuit) – a quantum circuit

Link the matrix implementations to the gate definitions of a circuit.

Warning

The linking happens in place (thus modifies the input circuit).

Parameters

circuit (qat.core.Circuit) – a quantum circuit

set_gate_set(gate_set)

Overrides the internal gate set with a new gate set.

Parameters

gate_set (GateSet) – a gate set