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bloq counts
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‎qualtran/resource_counting/__init__.py‎

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from ._costing import GeneralizerT, get_cost_value, get_cost_cache, query_costs, CostKey, CostValT
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from ._bloq_counts import BloqCount, QECGatesCost
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from . import generalizers

‎qualtran/resource_counting/_bloq_counts.py‎

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# Copyright 2023 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from collections import defaultdict
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from typing import Callable, Dict, Optional, Tuple, TYPE_CHECKING
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import attrs
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import networkx as nx
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from attrs import frozen
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from ._call_graph import get_bloq_callee_counts
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from ._costing import CostKey
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from .classify_bloqs import bloq_is_clifford
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if TYPE_CHECKING:
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from qualtran import Bloq
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logger = logging.getLogger(__name__)
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BloqCountDict = Dict['Bloq', int]
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@frozen
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class BloqCount(CostKey[BloqCountDict]):
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gateset_bloqs: Tuple['Bloq', ...]
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gateset_name: str
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@classmethod
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def for_gateset(cls, gateset_name: str):
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from qualtran.bloqs.basic_gates import TGate, Toffoli, TwoBitCSwap
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if gateset_name == 't':
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bloqs = (TGate(), TGate(is_adjoint=True))
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elif gateset_name == 't+tof':
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bloqs = (TGate(), TGate(is_adjoint=True), Toffoli())
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elif gateset_name == 't+tof+cswap':
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bloqs = (TGate(), TGate(is_adjoint=True), Toffoli(), TwoBitCSwap())
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else:
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raise ValueError(f"Unknown gateset name {gateset_name}")
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return cls(bloqs, gateset_name=gateset_name)
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@classmethod
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def for_call_graph_leaf_bloqs(cls, g: nx.DiGraph):
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leaf_bloqs = {node for node in g.nodes if not g.succ[node]}
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return cls(tuple(leaf_bloqs), gateset_name='leaf')
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def compute(
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self, bloq: 'Bloq', get_callee_cost: Callable[['Bloq'], BloqCountDict]
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) -> BloqCountDict:
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if bloq in self.gateset_bloqs:
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logger.info("Computing %s: %s is in the target gateset.", self, bloq)
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return {bloq: 1}
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totals: BloqCountDict = defaultdict(lambda: 0)
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callees = get_bloq_callee_counts(bloq)
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logger.info("Computing %s for %s from %d callee(s)", self, bloq, len(callees))
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for callee, n_times_called in callees:
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callee_cost = get_callee_cost(callee)
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for gateset_bloq, count in callee_cost.items():
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totals[gateset_bloq] += n_times_called * count
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return dict(totals)
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def zero(self) -> BloqCountDict:
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return {}
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def __str__(self):
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return f'{self.gateset_name} counts'
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@frozen(kw_only=True)
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class GateCounts:
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t: int = 0
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toffoli: int = 0
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cswap: int = 0
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and_bloq: int = 0
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clifford: int = 0
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def __add__(self, other):
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if not isinstance(other, GateCounts):
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raise TypeError(f"Can only add other `GateCounts` objects, not {self}")
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return GateCounts(
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t=self.t + other.t,
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toffoli=self.toffoli + other.toffoli,
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cswap=self.cswap + other.cswap,
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and_bloq=self.and_bloq + other.and_bloq,
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clifford=self.clifford + other.clifford,
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)
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def __mul__(self, other):
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if not isinstance(other, int):
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raise TypeError(f"Can only multiply `GateCounts` objects by integers, not {self}")
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return GateCounts(
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t=other * self.t,
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toffoli=other * self.toffoli,
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cswap=other * self.cswap,
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and_bloq=other * self.and_bloq,
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clifford=other * self.clifford,
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)
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def __rmul__(self, other):
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return self.__mul__(other)
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def __str__(self):
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strs = []
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for f in attrs.fields(self.__class__):
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val = getattr(self, f.name)
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if val != 0:
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strs.append(f'{f.name}: {val}')
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if strs:
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return ', '.join(strs)
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return '-'
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@property
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def total_n_magic(self):
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"""The total number of magic states.
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This can be used as a rough proxy for total cost. It is the sum of all the attributes
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other than `clifford`.
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"""
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return self.t + self.toffoli + self.cswap + self.and_bloq
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@property
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def total_n_magic(self):
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"""The total number of magic states.
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This can be used as a rough proxy for total cost. It is the sum of all the attributes
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other than `clifford`.
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"""
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return self.t + self.toffoli + self.cswap + self.and_bloq
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@frozen
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class QECGatesCost(CostKey[GateCounts]):
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"""Counts specifically for 'expensive' gates in a surface code error correction scheme."""
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ts_per_toffoli: Optional[int] = None
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toffolis_per_and: Optional[int] = None
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ts_per_and: Optional[int] = None
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toffolis_per_cswap: Optional[int] = None
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ts_per_cswap: Optional[int] = None
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def compute(self, bloq: 'Bloq', get_callee_cost: Callable[['Bloq'], GateCounts]) -> GateCounts:
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from qualtran.bloqs.basic_gates import TGate, Toffoli, TwoBitCSwap
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from qualtran.bloqs.mcmt.and_bloq import And
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# T gates
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if isinstance(bloq, TGate):
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return GateCounts(t=1)
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# Toffolis
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if isinstance(bloq, Toffoli):
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if self.ts_per_toffoli is not None:
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return GateCounts(t=self.ts_per_toffoli)
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else:
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return GateCounts(toffoli=1)
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# 'And' bloqs
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if isinstance(bloq, And) and not bloq.uncompute:
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if self.toffolis_per_and is not None:
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return GateCounts(toffoli=self.toffolis_per_and * self.ts_per_toffoli)
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elif self.ts_per_and is not None:
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return GateCounts(t=self.ts_per_and)
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else:
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return GateCounts(and_bloq=1)
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# CSwaps aka Fredkin
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if isinstance(bloq, TwoBitCSwap):
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if self.toffolis_per_cswap is not None:
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return GateCounts(toffoli=self.toffolis_per_cswap)
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elif self.ts_per_cswap is not None:
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return GateCounts(t=self.ts_per_cswap)
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else:
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return GateCounts(cswap=1)
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# Cliffords
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if bloq_is_clifford(bloq):
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return GateCounts(clifford=1)
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# Recursive case
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totals = GateCounts()
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callees = get_bloq_callee_counts(bloq)
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logger.info("Computing %s for %s from %d callee(s)", self, bloq, len(callees))
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for callee, n_times_called in callees:
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callee_cost = get_callee_cost(callee)
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totals += n_times_called * callee_cost
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return totals
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def zero(self) -> GateCounts:
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return GateCounts()
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def validate_val(self, val: GateCounts):
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if not isinstance(val, GateCounts):
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raise TypeError(f"{self} values should be `GateCounts`, got {val}")
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def __str__(self):
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gates = ['t']
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if self.ts_per_toffoli is None:
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gates.append('tof')
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if self.toffolis_per_and is None and self.ts_per_and is None:
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gates.append('and')
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if self.toffolis_per_cswap is None and self.ts_per_cswap is None:
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gates.append('cswap')
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return ','.join(gates) + ' counts'

‎qualtran/resource_counting/classify_bloqs.py‎

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classification = classify_bloq(k, bloq_classification)
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classified_bloqs[classification] += v * t_counts_from_sigma(k.call_graph()[1])
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return classified_bloqs
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def bloq_is_clifford(b: Bloq):
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from qualtran.bloqs.basic_gates import CNOT, Hadamard, SGate, TwoBitSwap, XGate, ZGate
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from qualtran.bloqs.mcmt.multi_control_multi_target_pauli import MultiTargetCNOT
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from qualtran.bloqs.util_bloqs import ArbitraryClifford
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if isinstance(b, Adjoint):
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b = b.subbloq
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if isinstance(
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b, (TwoBitSwap, Hadamard, XGate, ZGate, ArbitraryClifford, CNOT, MultiTargetCNOT, SGate)
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):
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return True
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return False

‎qualtran/resource_counting/generalizers.py‎

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import attrs
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import sympy
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from qualtran import Adjoint, Bloq
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from qualtran import Bloq
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PHI = sympy.Symbol(r'\phi')
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CV = sympy.Symbol("cv")
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def ignore_cliffords(b: Bloq) -> Optional[Bloq]:
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"""A generalizer that ignores known clifford bloqs."""
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from qualtran.bloqs.basic_gates import CNOT, Hadamard, SGate, TwoBitSwap, XGate, ZGate
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from qualtran.bloqs.mcmt.multi_control_multi_target_pauli import MultiTargetCNOT
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from qualtran.bloqs.util_bloqs import ArbitraryClifford
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from qualtran.resource_counting.classify_bloqs import bloq_is_clifford
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if isinstance(b, Adjoint):
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b = b.subbloq
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if isinstance(
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b, (TwoBitSwap, Hadamard, XGate, ZGate, ArbitraryClifford, CNOT, MultiTargetCNOT, SGate)
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):
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if bloq_is_clifford(b):
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return None
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return b
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