Change semantics of reset to also reset loss and leakage by david-pl · Pull Request #287 · QuEraComputing/ppvm

david-pl · 2026-11-06T18:57:44Z

Closes #283.

I had to add a new trait to implement the reset at the word-level. Otherwise, this would have led to conflicting implementations on PauliSum<T>.

…et_state - MR/MRX/MRY now read out first (lost -> None, leaked -> pinned bit), then do a full reset like R, so lost / leaked qubits come back live. - New I_ERROR[reset_state] tag maps to ResetState::reset_state, which resets live qubits only. - Python: reset_state on GeneralizedTableau and GeneralizedTableauSum. - Document the new reset semantics in the ppvm-usage skill. Refs #283 Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Reuse the true readout outcome to flip live qubits back to |0>, then reset loss and leakage, instead of a full `reset` that measures again. Refs #283 Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Copilot

🟡 Changes recommended

The API table incorrectly marks reset_state as unavailable for Python GeneralizedTableau and needs to reflect the support added by this PR.

1 open issue

Mark reset_state as supported in the P-T column · New

What changed in this PR

This PR addresses #283 by making standard resets recover lost and leaked qubits, while preserving the previous behavior through reset_state across the simulator APIs.

Changes:

Splits full resets from state-only resets and adds word-level reset support for Pauli propagation.
Exposes reset_state through Python bindings and the Stim parser/executor.
Adds regression tests and updates usage documentation.

File	Description
`skills/ppvm-usage/SKILL.md`	Documents full and state-only resets.
`ppvm-python/test/generalized_tableau/test_loss.py`	Tests Python reset recovery and state-only behavior.
`ppvm-python/src/ppvm/generalized_tableau.py`	Exposes and documents `reset_state`.
`ppvm-python/src/ppvm/generalized_tableau_sum.py`	Adds state-only resets for tableau sums.
`ppvm-python/src/ppvm/_core.pyi`	Declares native `reset_state` methods.
`crates/stim-parser/tests/proptest_ast.rs`	Includes state resets in property tests.
`crates/stim-parser/src/print/mod.rs`	Prints the `reset_state` extension.
`crates/stim-parser/src/pipeline/lower.rs`	Parses and validates the new reset tag.
`crates/stim-parser/src/instructions/mod.rs`	Updates supported-tag documentation.
`crates/stim-parser/src/ast/extended.rs`	Adds the state-reset instruction variant.
`crates/ppvm-traits/src/traits/reset.rs`	Defines state-only and word-level reset traits.
`crates/ppvm-traits/src/traits/mod.rs`	Exports the new reset traits.
`crates/ppvm-traits/src/traits/map.rs`	Adds one-to-many map accumulation.
`crates/ppvm-traits/src/map/hashmap.rs`	Implements sequential one-to-many accumulation.
`crates/ppvm-traits/src/map/dashmap.rs`	Implements parallel one-to-many accumulation.
`crates/ppvm-traits-2/src/lib.rs`	Exports `ResetState` at the crate root.
`crates/ppvm-traits-2/src/gates/mod.rs`	Re-exports the state-reset trait.
`crates/ppvm-traits-2/src/gates/measure.rs`	Separates full and state-only reset contracts.
`crates/ppvm-tableau/tests/gates.rs`	Tests full versus state-only lost-qubit resets.
`crates/ppvm-tableau/src/noise.rs`	Uses state resets internally and tests recovery.
`crates/ppvm-tableau/src/gates/reset.rs`	Implements full loss and leakage recovery.
`crates/ppvm-tableau-sum/tests/sampler_vs_pure.rs`	Checks reset consistency between backends.
`crates/ppvm-tableau-sum/src/gates/reset.rs`	Separates state reset from loss recovery.
`crates/ppvm-stim/tests/executor.rs`	Tests Stim reset and measurement-reset behavior.
`crates/ppvm-stim/src/validate.rs`	Accepts the state-reset instruction.
`crates/ppvm-stim/src/executor.rs`	Executes state resets and updates measurement-reset recovery.
`crates/ppvm-stim/benches/stim-circuits.rs`	Counts targets of state-reset instructions.
`crates/ppvm-python-native/src/interface_tableau.rs`	Binds tableau state resets to Python.
`crates/ppvm-python-native/src/interface_tableau_sum.rs`	Binds tableau-sum state resets to Python.
`crates/ppvm-pauli-word/src/word/data.rs`	Implements ordinary Pauli-word resets.
`crates/ppvm-pauli-word/src/loss/data.rs`	Implements lossy Pauli-word reset expansion.
`crates/ppvm-pauli-sum/src/sum/reset.rs`	Implements full reset propagation and regression tests.

_{Review effort: Balanced}

github-actions · 2026-11-06T19:03:35Z

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2026-11-09 09:03 UTC

Copilot

🔵 Needs a closer look

The availability table incorrectly marks reset_state as unsupported in Python, obscuring the newly exposed state-only reset API.

1 open issue

Mark reset_state as supported in the P-T column

_{Review effort: Balanced}

JonhasA

LGTM

Copilot

🟢 Approval recommended

The review has no active issues requiring changes.

No open issues 🎉

1 resolved since last review

Mark reset_state as supported in the P-T column

_{Review effort: Balanced}

## 🤖 New release * `ppvm-traits`: 0.2.1 -> 0.3.0 (⚠ API breaking changes) * `ppvm-pauli-word`: 0.2.1 -> 0.3.0 (✓ API compatible changes) * `ppvm-pauli-sum`: 0.2.1 -> 0.3.0 (✓ API compatible changes) * `ppvm-sym`: 0.2.1 -> 0.3.0 * `ppvm-tableau`: 0.2.1 -> 0.3.0 (✓ API compatible changes) * `stim-parser`: 0.2.1 -> 0.3.0 (⚠ API breaking changes) * `ppvm-stim`: 0.2.1 -> 0.3.0 (✓ API compatible changes) * `ppvm-tableau-sum`: 0.2.1 -> 0.3.0 (✓ API compatible changes) * `vihaco-circuit-isa`: 0.2.1 -> 0.3.0 * `ppvm-vihaco`: 0.2.1 -> 0.3.0 * `ppvm-tui`: 0.2.1 -> 0.3.0 * `ppvm-cli`: 0.2.1 -> 0.3.0 ### ⚠ `ppvm-traits` breaking changes ```text --- failure trait_added_supertrait: non-sealed trait added new supertraits --- Description: A non-sealed trait added one or more supertraits, which breaks downstream implementations of the trait ref: https://doc.rust-lang.org/cargo/reference/semver.html#generic-bounds-tighten impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/trait_added_supertrait.ron Failed in: trait ppvm_traits::traits::Reset gained ResetState in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/reset.rs:31 trait ppvm_traits::prelude::Reset gained ResetState in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/reset.rs:31 trait ppvm_traits::Reset gained ResetState in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/reset.rs:31 --- failure trait_method_added: pub trait method added --- Description: A non-sealed public trait added a new method without a default implementation, which breaks downstream implementations of the trait ref: https://doc.rust-lang.org/cargo/reference/semver.html#trait-new-item-no-default impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/trait_method_added.ron Failed in: trait method ppvm_traits::traits::ACMapAddAssign::map_flat_add_assign in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/map.rs:55 trait method ppvm_traits::prelude::ACMapAddAssign::map_flat_add_assign in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/map.rs:55 trait method ppvm_traits::ACMapAddAssign::map_flat_add_assign in file /tmp/.tmpOuypqr/ppvm/crates/ppvm-traits/src/traits/map.rs:55 ``` ### ⚠ `stim-parser` breaking changes ```text --- failure enum_variant_added: enum variant added on exhaustive enum --- Description: A publicly-visible enum without #[non_exhaustive] has a new variant. ref: https://doc.rust-lang.org/cargo/reference/semver.html#enum-variant-new impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/enum_variant_added.ron Failed in: variant ExtendedInstruction:ResetState in /tmp/.tmpOuypqr/ppvm/crates/stim-parser/src/ast/extended.rs:67 variant ExtendedInstruction:ResetState in /tmp/.tmpOuypqr/ppvm/crates/stim-parser/src/ast/extended.rs:67 variant ExtendedInstruction:ResetState in /tmp/.tmpOuypqr/ppvm/crates/stim-parser/src/ast/extended.rs:67 ``` <details><summary>Changelog</summary> ## `ppvm-cli` <blockquote> ## [0.3.0](v0.2.1...v0.3.0) - 2026-11-09 ### Other - Change semantics of reset to also reset loss and leakage ([#287](#287)) </blockquote> </details> --- This PR was generated with [release-plz](https://github.com/release-plz/release-plz/). Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

david-pl and others added 4 commits November 6, 2026 16:44

Make reset reset loss and leakage too

4000583

Rename word_reset

f039c32

perf(stim): avoid extra measurement in MR reset

2199c91

Reuse the true readout outcome to flip live qubits back to |0>, then reset loss and leakage, instead of a full `reset` that measures again. Refs #283 Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

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Merge branch 'main' into david/reset-everything

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Comment thread skills/ppvm-usage/SKILL.md Resolved

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JonhasA approved these changes Nov 8, 2026

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Some minor fixes

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david-pl merged commit d231c3c into main Nov 9, 2026
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github-actions Bot mentioned this pull request Nov 9, 2026

chore: release v0.3.0 #288

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Change semantics of reset to also reset loss and leakage - #287

Change semantics of reset to also reset loss and leakage#287
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