| --- |
| license: gemma |
| tags: |
| - coreai |
| - sentence-similarity |
| - feature-extraction |
| - apple-silicon |
| - on-device |
| --- |
| |
| # EmbeddingGemma 300m — Core AI export |
|
|
| [google/embeddinggemma-300m](https://huggingface.co/google/embeddinggemma-300m) as a |
| single static Core AI graph: the full sentence-transformers pipeline (transformer → |
| mean pooling → dense projection → L2 normalize) runs in-graph, so one call returns a |
| normalized 768-d embedding. On-device semantic search / RAG for macOS 27 / iOS 27 beta. |
|
|
| Runs out of the box with [CoreAIKit](https://github.com/john-rocky/coreai-kit)'s |
| `TextEmbedder`: |
|
|
| ```swift |
| let embedder = try await TextEmbedder() // downloads this repo |
| let doc = try await embedder.embed(document: "Tokyo is the capital of Japan.") |
| let query = try await embedder.embed(query: "what is the capital of Japan") |
| let score = TextEmbedder.cosineSimilarity(doc, query) |
| ``` |
|
|
| Retrieval prompt prefixes (`task: search result | query: ` / `title: none | text: `) |
| are applied automatically by `TextEmbedder`. |
|
|
| ## Bundle layout |
|
|
| ``` |
| model/ |
| ├── embeddinggemma-300m_float32_static.aimodel |
| ├── tokenizer/ (HF tokenizer files) |
| └── reference.json (torch reference cosines used by the parity test) |
| ``` |
|
|
| ## Graph contract |
|
|
| | | name | shape | dtype | |
| |---|---|---|---| |
| | input | `input_ids` | [1, 256] | int32 (pad id 0, mask 0 over padding) | |
| | input | `attention_mask` | [1, 256] | int32 | |
| | output | `embedding` | [1, 768] | fp32, L2-normalized | |
|
|
| Precision: fp32. Cross-runtime parity vs the torch SentenceTransformer pipeline is |
| exact to 6 decimal places (see reference.json). fp16 variants (full cast AND |
| mixed-precision autocast) produce NaN embeddings on-device — Gemma3 activations |
| overflow half precision — so fp32 is shipped; a smaller int8 variant is future work. |
|
|
| ## License |
|
|
| Gemma Terms of Use (see the upstream model card). Conversion script: this repo's |
| sibling, based on apple/coreai-models' recipe patterns (BSD-3-Clause). |
|
|
