# CUDA Backend Analysis — Index
**Date:** 2026-04-19
**Analyzed version:** `hive-gpu 0.1.10`
**Scope:** Current state of the CUDA backend, gaps versus the Metal reference backend, and modernization plan.
## Documents
1. [Executive Summary](01-executive-summary.md)
2. [Current State of the Code](02-current-state.md)
3. [Gap Analysis vs. Requirements](03-gap-analysis.md)
4. [Architectural Decisions](04-architecture-decisions.md)
5. [Implementation Plan](05-implementation-plan.md)
6. [Risks and Mitigations](06-risks-and-mitigations.md)
7. [Impact on the Rest of the Project](07-project-impact.md)
8. [Next Immediate Steps](08-next-steps.md)
## At a Glance
- **Maturity:** Stub (≈5% complete). Compiles nothing GPU-related, returns `"not implemented yet"` on almost every path.
- **Feature flag `cuda` in [Cargo.toml:39](../../../Cargo.toml#L39)** is empty — `cudarc` is commented out.
- **Estimated effort** for functional parity with Metal: **15–20 dev-days**, plus 7 days if HNSW is required in v1.
- **Recommended binding:** [`cudarc`](https://crates.io/crates/cudarc) (pure-Rust, driver API).
- **Kernel strategy:** embedded PTX (offline-compiled with `nvcc`) in v1; `build.rs` multi-SM in v2.