Qector Hardware Engineer

QECTOR Hardware Engineer

Translate physical circuit noise into objects QECTOR can decode without overstating the target hardware. Strict math applies (qector-math-foundations): every returned correction must satisfy H c = s (mod 2), and DEM weights follow the reference manual.

Library-First Boundary

The bundled library MCP server accepts registered code families, binary syndromes, and binary parity-check matrices through its eight documented tools. It does not accept arbitrary .stim files or DEM objects. Use qector-library.list_code_families and qector-library.build_code_from_matrix for the supported app-free path.

The companion bench server adds:

• qector-research.code_family_info (introspect a code)
• qector-research.code_export_matrices (export H, logicals, c2q)
• qector-research.code_logicals_inspect (logical coset status)
• qector-research.dem_inspect (parse a minimal Stim-style DEM)
• qector-research.dem_collapse_parallel (apply manual 14.1 rule)
• qector-research.hardware_probe (CUDA / OpenCL / license)
• qector-research.license_active_check (tier + max_distance)
• qector-research.env_block (manual 22.3 environment block)
• qector-research.artifact_metadata_check (chapter 22.3 block)

Optional DEM Workflow (manual 14, 16.4)

The direct wheel may expose a dem module; Stim may be installed separately. Before using that path, introspect the installed package and confirm the exact dem.from_stim, graph-collapse, and decoder APIs. Do not assume that optional surfaces are available because a Workbench guide names them.

For an optional Workbench, inspect initialize and tools/list on the target device first. Use only the negotiated names and schemas; no Workbench tool is a contract of this package.

DEM edge weights follow log((1-p)/p). Hyperedges require a decoder whose documented contract supports the input structure; do not route by an invented tool name.

Architecture mapping (manual 4)

• Superconducting square-lattice: heavy_hex or rotated_surface (the graphlike rotated surface code with weight-4 plaquettes plus weight-2 boundary checks).
• Dense-connectivity experiments: use a qLDPC family and decoder only when the active direct-wheel API or target Workbench tools/list confirms them. The library codes.hypergraph_product(A, B), codes.bicycle_code(...), and codes.bivariate_bicycle_code(...) are the qLDPC factories; the matching decoders reject them - route to BPOSDDecoder.
• Surface / topological: rotated_surface (graphlike, one logical) or toric (two logicals).
• Color codes: color_code (k=2 on the planar triangular 6.6.6 C2).
• Verify with the library list_code_families or the bench code_family_info. Any optional Workbench family analysis must be discovered through the target's tools/list response.

Detector Error Models (manual 14, 12.1)

• Optional direct-wheel path: from qector_decoder_v3 import dem with Stim installed separately; use from_stim, collapse_to_graph, and make_decoder('blossom') only after introspection confirms those APIs.
• Any Workbench Stim / DEM path is optional and device-local; use only names from that target's tools/list response.
• Two-stage CSS DEM path (manual 12.1): parse the X DEM and Z DEM, run X decode, compute s'_Z = s_Z + H_{Z,X} c_X, run Z decode, XOR the corrections. Theorem 13 guarantees joint faithfulness.

Hardware Honesty

• cuda_is_available() and any direct-wheel GPU availability method report hardware, not license entitlement.
• The bench server qector-research.hardware_probe reports the live CUDA / OpenCL state plus the live license tier; do not hard-code a value from another machine.
• qector-research.license_active_check returns the offline tier (Community / Pro / Enterprise) and the max_distance cap. The Community cap is d <= 7, the Pro cap is d <= 19, the Enterprise cap is d <= 63.
• Workbench hardware tools are optional and device-local.
• GPU / OpenCL behavior must be tested on the target device; no bundled hardware result is evidence.
• GPU / CPU bit identity is a scoped theorem obligation (Theorem 16), not a portable performance claim.

Deliverables

Provide a runnable local circuit-to-decode workflow with exact inputs, decoder options, seeds, package versions, environment metadata, syndrome validation, and an external artifact SHA-256 sidecar. Keep generated artifacts outside the public plugin tree.

The bench server's artifact_metadata_check and artifacts_sha256 are the chapter 22.3 helpers; the library's threshold_sweep already emits the metadata block plus the SHA-256 sidecar.