| name | abi-superpower-wdbx-compute |
| description | WDBX compute backend superpower. CPU/GPU/NPU/TPU backend selector with deterministic CPU SIMD fallback. ANE detection, remote TPU dispatch. |
| superpower | {"command":"execute","parameters":[{"name":"action","type":"string","enum":["info","select","backend","remote"],"description":"Compute action"},{"name":"backend","type":"string","enum":["cpu","gpu","npu","tpu","auto"],"description":"Target backend"},{"name":"endpoint","type":"string","description":"Remote compute endpoint (TPU)"}]} |
ABI Superpower: WDBX Compute
Exposes the WDBX compute backend selector as a superpower. Dynamic backend selection across CPU (scalar/AVX2/AVX-512/NEON), GPU (CUDA/Metal/Vulkan), NPU (ANE detection), and TPU (remote dispatch transport). Always degrades to deterministic CPU SIMD path — native accelerator kernels are NOT linked.
Actions
info
Show compute backend matrix (availability + dispatch status):
/abi-superpower-wdbx-compute info
Output includes:
- CPU: scalar, AVX2, AVX-512, NEON (host-detected via
std.simd.suggestVectorLength)
- GPU: CUDA, Metal, Vulkan (capability reporting only — no native kernels linked)
- NPU: ANE hardware presence (truthful detection, no execution)
- TPU: Report-only endpoint metadata (
ABI_REMOTE_COMPUTE_ENDPOINT) plus a
separately tested reference TCP transport
select
Select and initialize a backend:
/abi-superpower-wdbx-compute select --backend auto
Options: cpu, gpu, npu, tpu, auto (prefers Metal on macOS, else CPU SIMD)
backend
Get details for a specific backend:
/abi-superpower-wdbx-compute backend --backend metal
remote
Show or plan remote TPU reference transport configuration:
/abi-superpower-wdbx-compute remote --endpoint http://tpu-server:8080
Backend Matrix (Honest)
| Backend | Available | Dispatches | Reality |
|---|
| CPU SIMD | Always | ✅ Always | Vectorized @Vector with host-matched width |
| Metal (macOS) | On macOS | ⚠️ Only if g_metal_context.init() succeeds | Pure-Zig ObjC FFI, runtime MSL compile |
| CUDA | Never | ❌ No | Capability reported, not linked |
| Vulkan | Never | ❌ No | Needs loader/ICD + SPIR-V; not linked |
| ANE (NPU) | On Apple Silicon | ❌ No | compute.aneHardwarePresent() truthfully detects; needs CoreML/ObjC |
| TPU (remote) | Reference only | ❌ Not production-wired | remote_compute.zig has a loopback-tested DOT transport; the environment endpoint is report-only |
Implementation
| Component | Source | Role |
|---|
| Backend Selector | src/features/wdbx/compute.zig | Dynamic CPU/GPU/NPU/TPU selection |
| CPU SIMD | src/features/wdbx/hnsw_distance.zig | @Vector cosine, std.simd.suggestVectorLength |
| GPU | src/features/gpu/vector_ops.zig + compute_api.zig | cosineSimilarity() via Metal, CPU fallback |
| NPU Detection | src/features/wdbx/compute.zig | aneHardwarePresent() — truthful |
| Remote TPU | src/features/wdbx/remote_compute.zig | Reference DOT transport; no production caller wires ABI_REMOTE_COMPUTE_ENDPOINT |
| Parity Test | src/features/gpu/compute_api.zig | CPU/GPU dot-product parity |
CLI Access
abi wdbx compute info
Feature Gates
Requires feat-wdbx=true and feat-gpu=true (both default). When disabled, returns FeatureDisabled.
Claim Boundary
Per docs/spec/wdbx-north-star.mdx §3.3 and docs/contracts/external-claims-audit.mdx:
- ✅ Dynamic backend selector across CPU/GPU/NPU/TPU
- ✅ CPU SIMD parity test against GPU path
- ✅ ANE hardware detection (truthful)
- ✅ Remote TPU dispatch transport (operator's endpoint)
- ❌ Native CUDA/Metal/Vulkan/ANE kernel execution NOT linked
- ❌ No bundled accelerator — TPU points at operator's own service
- ❌ ANE execution requires CoreML/ObjC (not pure Zig) — disclosed non-goal
