| # Multilingual host contract |
|
|
| This is the Android integration summary for the pinned multilingual Laya checkpoint |
| `convaiinnovations/laya@1c5edc17a7acd8701df6fc341c0d179f1c62c982` and upstream laya 0.3.4. |
| The complete Python host contract and executable reference are shipment artifacts |
| `HOST_CONTRACT.md` and `laya_host.py` in [litert-community/Laya-Multilingual-LiteRT](https://huggingface.co/litert-community/Laya-Multilingual-LiteRT). The app uses the embedding-input |
| graph interface below. |
|
|
| ## Tokenizer and prompt |
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|
| `LayaTokenizer` loads the complete checkpoint BPE JSON with 256,000 vocabulary entries. It |
| matches added tokens, replaces ASCII spaces with U+2581, applies Metaspace with always-prepend |
| and splitting, merges by rank, and falls back to UTF-8 byte tokens. Text fragments use |
| `addSpecialTokens = false`; the builder inserts CLS **2**, SEP **1**, and MASK **4** itself. |
| PAD is **0** and UNK is **3**. No extra Unicode normalization is applied. |
|
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| Each call contains one question, with schema type `choice`, `score`, or `noul`. The builder |
| preserves question and option order, encodes the literal `type question: instructions` prefix, |
| and renders the upstream criteria without changing them. Options have one MASK marker followed |
| by at most 48 text tokens. With head budget 256, an option budget below 16 triggers the exact |
| upstream squeeze rule; the instruction slice keeps `max(8, remaining budget)` tokens. |
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| The sequence is CLS + instruction + SEP + marked options + SEP + state + SEP. String state |
| passes through; map/list state uses Python-compatible insertion order, Unicode, JSON |
| booleans/null, comma-space and colon-space separators. Literal `<mask>` in text is replaced |
| by an ASCII space. State tokens are truncated on the right to fit the selected static window; |
| the final whole-sequence slice and marker filter follow upstream. A row that loses an option |
| marker is rejected before inference. |
|
|
| ## Graph inputs and outputs |
|
|
| The app uses one `serving_default` signature per graph. Buffers are mapped by signature names |
| and runtime order. All inputs and outputs below are float32; N is 256 in the UI. |
|
|
| | Graph | Direction | Name | Shape | |
| |---|---|---|---| |
| | Main | Input | `inputs_embeds` | `[1,N,768]` | |
| | Main | Input | `attention_mask` | `[1,N]` | |
| | Main | Input | `qtype_onehot` | `[1,3]` | |
| | Main | Output | `token_logits` | `[1,N]` | |
| | Main | Output | `pooled_cls` | `[1,768]` | |
| | Action | Input | `pooled_cls` | `[1,768]` | |
| | Action | Input | `feats` | `[1,4]` | |
| | Action | Output | `act_logits` | `[1,2]` | |
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|
| `LayaEmbeddings` maps the little-endian FP16 `[256000,768]` table read-only and converts gathered |
| rows to float32. Right padding gathers token **0**, including its actual vector; it does not |
| insert an all-zero vector. Attention is 1 for real sequence positions and 0 for padding. |
| Question-type order is choice, score, noul. The whole table's FP16 cast round-trip maximum |
| absolute error is 0. WFP16 storage changes only fully connected weights in the main graph. |
|
|
| ## Decoder and calibration |
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|
| Gather marker logits, then compute stable raw softmax. The action features are raw top-1 |
| probability, top-1 minus top-2, normalized raw entropy using `k = max(K,2)` and a log floor |
| of `1e-9`, and `k/255`. Action probability is `softmax(act_logits)[0]`; it is uncalibrated. |
|
|
| Option temperature first uses `temperature_by_options` with bucket suffix `2`, `3-5`, `6-10`, |
| or `11+`, then `temperature[qtype]`. Its floor is `1e-3`. **Calibrated** loads the supplied JSON; |
| **T=1 (uncalibrated)** uses identity temperatures. The calibrated UI and T=1 conversion gates |
| are intentionally separate measurements. |
|
|
| Choice returns the first argmax label and ordered probabilities. Score returns the expected |
| zero-based index, all probabilities, and the original legend. Noul returns continuous true |
| probability. Choice/score confidence is normalized entropy confidence with a `1e-12` floor; |
| noul confidence is `max(pTrue, 1-pTrue)`. Values are rounded to four decimal places using |
| Python's ties-to-even rule on the represented binary double, after intermediate math. |
|
|
| ## Executable checks |
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|
| The host implementation is in `app/src/main/java/com/laya/`: `LayaTokenizer.kt`, |
| `LayaPromptBuilder.kt`, `LayaDecoder.kt`, `LayaCalibration.kt`, `LayaEmbeddings.kt`, and |
| `LayaEngine.kt`. JVM parity tests compare all captured IDs, marker positions, official and |
| calibrated answer dictionaries, state serialization, and embedding values. Fixture layout and |
| counts are documented in [TEST_DATA.md](../scripts/TEST_DATA.md). No JVM parity result substitutes |
| for the on-device tokenizer and numerical gate. |
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|
