fix-mps-encoding-non-factorizing: §1-§8 implementation - #48
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Implement the cross-coupled-by-sum bond-2 MPS encoding (Alternative A
from the change's design.md) so the canonical hierarchical-polysemantic
example has a Gram that genuinely differs from the rung-0 product-state
factorization, fixing the silent factorization documented in the
post-mortem of `add-mps-concept-encoding`.
- compiler helper: generalize the Ry-segment matcher in
compute_concept_gram_mps to accept linear-combination angle
expressions via ast walking; new `unrecognized_angle_expression`
error kind for non-linear forms
- angle evaluator: extend evaluate_angle to recurse on top-level + / -
so `Ry(qs[1], a + b)` parses cleanly through markdown_parser and the
effect_parser
- example: re-pin to `Ry(q0,a); CNOT; Ry(q1, a+b); CNOT; Ry(q2, b+c)`;
refresh tier table (sub-mate 0.882 / super-sib {0.335, 0.593, 0.753}
/ cross [0.000, 0.178]), heatmap, polysemy column, β values, and
add the `non_factorized_gram` verification rule
- demo: update prepare/query circuits to the cross-coupled angles,
re-pin the tier ranges, and reword §6 narrative to ground the
hierarchy in the cross-coupling rather than the staircase entanglement
- docs: README hierarchical-polysemy section, post-mortem appended to
archived `add-mps-concept-encoding/design.md` (only edit to archived
content), and a "Schmidt rank > 1 ≠ non-factorized overlap" caveat
box plus updated rung-1 entry in the research note
- tests: re-pin tier-band assertions, add the non-factorization
assertion, replace the obsolete mixed-signs / param-position-mismatch
tests with new tests for cross-coupled, single-bound-param-degenerate,
swapped-position, and unrecognized_angle_expression sad paths
- tech-debt: add §5.7 (verifier blind spot — Gram factorization vs.
encoding entanglement) with a back-link from §5.6
OpenSpec: validates strict; all 29 change tasks ticked.
Test suite: 774 passed, 6 skipped. Demo passes with max error 0.0077
< 0.0469 threshold.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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jascal
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#49) Bumps version 0.6.0 → 0.7.0 and lands the post-merge documentation sync after PR #46 (`add-mps-concept-encoding`) and PR #48 (`fix-mps-encoding-non-factorizing`). - README: move MPS concept encoding (rung 1) from "Near-term — implementation pending" into "Recently shipped" with PR refs and the cross-coupled-by-sum encoding formula. - CHANGELOG: convert "Unreleased" → "0.7.0 (2026-05-01)"; correct the stale tier values (`super-group-sibling [0.47, 0.54]` → `{0.335, 0.593, 0.753}`, `cross-group [0.12, 0.25]` → `[0.000, 0.178]`) and the encoding (single-bound-param → cross-coupled-by- sum) in the hierarchical-polysemy entry; add Changed entry for the generalized angle parser; add Fixed entry for `fix-mps-encoding-non-factorizing` referencing PR #48 and tech- debt §5.7. - Research doc: link the rung-1 entry in `docs/research/polysemantic-encoding-beyond-product-states.md` to the merged PRs (#46 + #48) and the post-mortem in `add-mps-concept-encoding/design.md`. - OpenSpec: archive `add-mps-concept-encoding` (25/26 — task 4.2 superseded by `fix-mps-encoding-non-factorizing`) and `fix-mps-encoding-non-factorizing` (✓ Complete) under `openspec/changes/archive/2026-05-02-…`. Both updates flow through to `openspec/specs/{compiler,language}/spec.md`. - Tech debt: append §5.8–§5.15 from a post-merge self-review of PR #48 (HIGH: scientific-notation regression in `_split_linear_combination`; MEDIUM: error-message drift, etc.). Note: the demo-smoke step in `verify-examples.yml` is split out of this commit (PAT lacks workflow scope) — to be added via the GitHub UI as a follow-up. Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
This was referenced May 2, 2026
jascal
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… polish (#58) Cluster of small concept_gram_mps fixes from the 2026-05-01 PR #48 self-review and Sonnet 4.6's PR #45 review: - §3.11: fold the angle-matrix build into the per-call-site loop and wrap `float(b.value)` in a try/except that re-raises as `MpsGramConfigurationError` naming the call site, action, argument index, and offending value. Defensive guard for programmatically- built `QMachineDef`s; the parser only ships int/float literals into `BoundArg.value` today, so this is purely a contract hardening. - §5.12 + §5.13: refactor the Mult branch of `_parse_linear_combination` through a new `_as_numeric_const` helper that recognizes both bare `Constant` and `UnaryOp(USub|UAdd, Constant)` shapes. As a side effect this also accepts the canonical `-2*a` form (previously silently rejected — the AST is `BinOp(Mult, UnaryOp(USub, Constant), Name)`, not `BinOp(Mult, Constant(-2), Name)`). The two-constants case (`2*3`) now raises with a clearer "no parameter reference" message instead of the misleading "two non-constant terms" wording. - §5.10: cover the spec-listed but untested `unrecognized_angle_ expression` triggers — bare numeric literal (`Ry(qs[1], 2.5)`) and power expression (`a**2`). - §5.11: focused unit test for the inverse-form linear-combination path, asserting `|gram_inverse| == |gram_prep|` on shared angle triples — pins the helper's `is_inverse=True` cross-coupled branch directly rather than via the example pipeline. - §5.15: update the live spec example at `openspec/specs/language/spec.md` to reflect the qiskit compiler's actual fully-evaluated-float emission (`qc.ry(-0.85, 2)`) instead of the misleading symbolic `qc.ry(a_value + b_value, 1)` form. (The `MpsGramConfigurationError` docstring half of §5.15 was already addressed by an interim PR.) - §5.2: bump `docs/compute-needs.md` from "All 15 example machines" to "All 19" — the README references had already drifted forward via interim PRs; only this doc remained stale. 852 tests pass, no new ruff violations on touched files. Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
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Summary
design.md) —Ry(q0, a); CNOT; Ry(q1, a+b); CNOT; Ry(q2, b+c)— so the canonical hierarchical-polysemantic example has a Gram that genuinely differs from the rung-0 product-state factorization. Fixes the silent factorization documented in the post-mortem ofadd-mps-concept-encoding.compute_concept_gram_mpsto accept linear-combination angle expressions via Pythonastwalking; extendevaluate_angleto recurse on top-level+/-so the new effect strings parse end-to-end. Re-pin example, demo, README, research note, tests, and add tech-debt §5.7 with a back-link from §5.6.Test plan
openspec validate fix-mps-encoding-non-factorizing --strictreturns validopenspec listshows the change as✓ Completepytest tests/passes (774 / 6 skipped)tests/test_examples.py::TestExamples::test_larql_polysemantic_hierarchical_pipelinere-pinned tier bands + non-factorization assertion both passtests/test_compiler.py::TestComputeConceptGramMps19 cases pass (incl. new cross-coupled, single-bound-param-degenerate, swapped-position, andunrecognized_angle_expressionsad paths)python demos/larql_polysemantic_hierarchical/demo.pyruns end-to-end and prints PASSadd-mps-concept-encoding/design.mdis the only edit to archived content🤖 Generated with Claude Code