Crate paulistrings 

The Rust core of paulistrings-rs: operators evolved in the Pauli basis under gates and noise channels, stored as a GF(2)-bucketed PauliSum and optionally partitioned over NUMA domains, MPI ranks or CUDA devices.

These docs are a developer guide; the user-facing API is the Python package, documented at https://lkdvos.github.io/paulistrings-rs/.

Structs

And

Both policies: a term is kept if both keep it, and both layer passes run, first then second.

ApproxTopN

Retain n terms, cutting at an octave of |c|² instead of selecting exactly.

BuildAccumulator

Incremental builder for a crate::PauliSum from unsorted terms; repeated keys sum.

Circuit

An ordered list of channels on num_qubits qubits, user-defined crate::Channel impls included.

CoefficientThreshold

Drop terms whose coefficient magnitude is at most epsilon.

CollapseSample

Replace the sum by one Pauli string, drawn with probability |c|² / Σ|c|² and given coefficient 1, whenever it holds more than cache terms.

CpuSet

A set of logical CPU indices; an unsorted literal is tolerated, since every consumer normalizes.

DeviceLayerRecord

What one device partition counted for a layer beyond the shared record.

DistributedSum

One process’s partition of a sum split across a Transport’s group, held across calls so a driver scatters once, steps many times and gathers once.

Gf2Hash

The GF(2)-linear hash h(v) = H·v from a Pauli key v = (x, z) to a bucket index, for a dense random H drawn from a seed.

LayerScratch

Reusable layer working set for propagate_with, which keeps its capacity across layers and calls and carries the opt-in traces.

Or

Either of two per-term filters: a term is kept if either keeps it.

OutputBuffer

The terms one Channel::apply call emits, pushed with push.

PartitionConfig

Placement plus the knobs the partitioned engine reads alongside it.

PartitionLayerRecord

What one layer did across the whole group; the per-partition vectors are indexed by rank.

PartitionRows

The p GF(2) rows part(v) = P·v that split a sum across 2^p partitions: a partition holds exactly the terms with part(v) equal to its rank.

PartitionRuntime

The resolved placement and its pinned pools, built once and shared behind an Arc by every PartitionedSum that runs on it.

PartitionTrace

Per-layer records of propagations in application order, accumulated until drained by a driver’s take_trace.

PartitionedSum

A PauliSum split across the partitions of a PartitionRuntime, held across calls so a driver scatters and gathers once.

PauliRotation

A rotation U = exp(-i · θ · P / 2) about a Pauli generator P of any weight.

PauliString

A Pauli operator on up to 64·W qubits, W being the number of 64-bit words per x/z part.

PauliSum

Weighted sum of Pauli strings, stored as structure-of-arrays columns partitioned into buckets by a GF(2)-linear hash.

Phase

A phase factor i^k with k ∈ {0, 1, 2, 3}; + multiplies phases.

ProductBasis

A product of single-qubit stabilizer states, one per qubit: on qubit q an axis A_q ∈ {X, Y, Z} with a sign s_q ∈ {+1, -1}, i.e. |ψ⟩ = ⊗_q |A_q, s_q⟩.

PropagateOptions

Tuning knobs for propagate_with; Default is what propagate uses.

PtmChannel

A one- or two-qubit gate or noise channel, stored as its Pauli-transfer matrix.

ScatterOptions

How a scatter_with runs its partitions and picks the rows the sum splits by.

StabilizerState

A stabilizer state on num_qubits qubits, held as a reduced tableau of signed generators.

TopN

Retain the n terms of largest coefficient magnitude.

WeightCutoff

Drop terms whose Pauli weight (number of non-identity qubits) exceeds k.

Enums

BuiltinTruncation

Any builtin policy or combinator as one runtime value, the form the device drivers take.

Direction

Propagation direction: channels in order, or in reverse with adjoints for backpropagating observables.

PartitionRowPolicy

Which partition rows a scatter splits by: a seeded GF(2)-random draw, or a qubit cut that keeps a channel local when its qubits share a block.

PauliAxis

One of the three single-qubit Pauli axes: the axis a ProductBasis qubit is an eigenstate of.

Placement

How partitions map onto the machine.

ScatterRows

The partition rows a scatter_with splits by.

StabilizerError

Why a set of generators does not define a stabilizer state.

TopologyError

What can go wrong discovering topology or resolving a PartitionConfig.

Constants

P_MAX_BITS

Maximum number of partition bits, i.e. P ≤ 64 partitions.

Traits

Channel

A gate or noise channel: maps a Pauli string to a small weighted sum of Pauli strings.

Collectives

The group operations a partition needs besides the exchange: its rank, the reductions, and a barrier.

Transport

The per-layer all-to-all exchange between the partitions of a group.

TruncationPolicy

A truncation strategy: a per-term filter, a per-layer pass, or both.

Functions

numa_nodes

The NUMA nodes visible in the current affinity mask, ascending by node id, each intersected with the mask.

propagate

Propagate sum through circuit under policy.

propagate_partitioned

Propagates sum through circuit on a partitioned engine built from config, and gathers the result.

propagate_with

propagate with a caller-held LayerScratch and PropagateOptions.

support_mask

Pack qubit indices into a Channel::support bitmask; order and duplicates do not matter.