catalyst.passes.merge_ppr_ppm¶

merge_ppr_ppm(qnode=None, *, max_pauli_size=0)[source]¶

Specify that the MLIR compiler pass for absorbing Clifford Pauli Product Rotation (PPR) operations, \(\exp{iP\tfrac{\pi}{4}}\), into the final Pauli Product Measurement (PPM) will be applied.

For more information regarding to PPM, check out the compilation hub.

Parameters:

fn (QNode) – QNode to apply the pass to
max_pauli_size (int) – The maximum size of the Pauli strings after merging.

Returns:

~.QNode

Example

In this example, the Clifford+T gates will be converted into PPRs first, then the Clifford PPRs will be commuted past the non-Clifford PPR, and finally the Clifford PPRs will be absorbed into the Pauli Product Measurements.

import pennylane as qml
from catalyst import qjit, measure

ppm_passes = [("PPM",["to-ppr", "commute-ppr","merge-ppr-ppm",])]

@qjit(pipelines=ppm_passes, keep_intermediate=True, target="mlir")
@qml.qnode(qml.device("lightning.qubit", wires=1))
def circuit():
    qml.H(0)
    qml.T(0)
    return measure(0)

print(circuit.mlir_opt)

Example MLIR Representation:

. . .
%2 = qec.ppr ["X"](8) %1 : !quantum.bit
%mres, %out_qubits = qec.ppm ["X"] %2 : !quantum.bit
. . .

If a merging resulted in a PPM acting on more than max_pauli_size qubits (here, max_pauli_size = 2), that merging would be skipped.

from catalyst import measure, qjit
from catalyst.passes import to_ppr, merge_ppr_ppm

pips = [("pipe", ["enforce-runtime-invariants-pipeline"])]

@qjit(pipelines=pips, target="mlir")
@to_ppr
@merge_ppr_ppm(max_pauli_size=2)
@qml.qnode(qml.device("lightning.qubit", wires=3))
def circuit():
    qml.CNOT([1, 2])
    qml.CNOT([0, 1])
    qml.CNOT([0, 2])
    return measure(0), measure(1), measure(2)

print(circuit.mlir_opt)

Example MLIR Representation:

. . .
%3:2 = qec.ppr ["Z", "X"](4) %1, %2 : !quantum.bit, !quantum.bit
. . .
%mres, %out_qubits:2 = qec.ppm ["Y", "Z"](-1) %3#1, %4 : !quantum.bit, !quantum.bit
. . .

code/api/catalyst.passes.merge_ppr_ppm

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catalyst.passes.merge_ppr_ppm¶

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