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  3. catalyst.passes.ppm_specs

catalyst.passes.ppm_specs

ppm_specs(fn, only_disjoint_qubit: bool = False)[source]

This function returns following Pauli product rotation (PPR) and Pauli product measurement (PPM) specs in a dictionary:

  • Pi/4 PPR (count the number of clifford PPRs)

  • Pi/8 PPR (count the number of non-clifford PPRs)

  • Pi/2 PPR (count the number of classical PPRs)

  • Max weight for pi/8 PPRs

  • Max weight for pi/4 PPRs

  • Max weight for pi/2 PPRs

  • Number of logical qubits

  • Number of PPMs

  • depth: number of PBC layers

  • depth_type: 0 if commuting ops on overlapping qubits may share a layer; 1 if only ops with disjoint qubit support may share a layer

Note

It is recommended to use pennylane.specs() instead of ppm_specs to retrieve resource counts of PPR-PPM workflows.

When there is control flow, this function can count the above statistics inside for loops with a statically known number of iterations. For all other cases, including dynamically sized for loops, and any conditionals and while loops, this pass exits with failure.

Parameters:

  • fn (QJIT) – qjit-decorated function for which ppm_specs need to be printed.

  • only_disjoint_qubit (bool) – If True, depth is computed using disjoint-qubit layering (depth_type 1). If False (default), commuting ops on overlapping qubits may share a layer (depth_type 0). Passed to the ppm-specs MLIR pass as disjoint-qubit.

Returns:

A Python dictionary containing PPM specs of all functions in fn.

Return type:

dict

Example

import pennylane as qp
import catalyst
from catalyst.passes import ppm_specs, to_ppr

@qp.qjit(target="mlir")
@to_ppr
@qp.qnode(qp.device("lightning.qubit", wires=2))
def f():
    qp.H(0)
    qp.S(1)
    qp.T(0)
    qp.CNOT(wires=[0, 1])
    return qp.expval(qp.Z(0))

print(ppm_specs(f))
print(ppm_specs(f, only_disjoint_qubit=True))

Example output:

{'f_0': {'depth': 4, 'depth_type': 0, 'logical_qubits': 2, 'max_weight_pi4': 2,
         'max_weight_pi8': 1, 'pi4_ppr': 7, 'pi8_ppr': 1}}
{'f_0': {'depth': 7, 'depth_type': 1, 'logical_qubits': 2, 'max_weight_pi4': 2,
         'max_weight_pi8': 1, 'pi4_ppr': 7, 'pi8_ppr': 1}}
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