--- library_name: transformers license: "cc-by-nc-sa-4.0" tags: - protein-language-model - fastplms --- # ANKH-Base ## Model overview `Synthyra/ANKH_base` packages the `ElnaggarLab/ankh-base` checkpoint with the FastPLMs runtime for Hugging Face Transformers. It accepts amino-acid sequences tokenized for encoder or sequence-to-sequence use. The repository uses the standard Transformers loading interface with `trust_remote_code=True`. See Technical details for each registered class and whether its weights come from the checkpoint. The sequence- and token-classification classes reuse the pretrained backbone, but their task heads are newly initialized. Fine-tune those heads before interpreting their logits as predictions. ## Install and platform requirements Install the direct dependencies published with this model: ```bash python -m pip install -r \ "https://huggingface.co/Synthyra/ANKH_base/resolve/main/requirements.txt" ``` The FastPLMs implementation itself is embedded in the model repository. Transformers loads it through `trust_remote_code=True`. This model requires Python 3.11-3.14, PyTorch 2.13, and Transformers 5.13. The CPU gate covers small offline tests. Published checkpoint throughput and parity require the documented device tier. The Hub quick start needs network access for the first download. For an air-gapped run, build the manifest-pinned local artifact first and use the offline example. ## Quick start ```python from transformers import AutoModel model_id = "Synthyra/ANKH_base" model = AutoModel.from_pretrained( model_id, trust_remote_code=True, attn_implementation="sdpa", ).eval() ``` For offline validation, replace `model_id` with the manifest-built `dist/hub/ANKH_base` path. Pass `local_files_only=True`. ## Attention backends The quick start uses `sdpa`. Available backends are `eager`, `sdpa`. Requesting an unavailable backend raises instead of silently changing implementation. `output_attentions=True` can use the documented one-call eager fallback to materialize attention tensors. The configured backend does not change. ## Tokenization and forward inference `Synthyra/ANKH_base` contains the complete encoder-decoder checkpoint. `AutoModel` loads the encoder without the decoder. `AutoModelForSeq2SeqLM` loads the encoder, decoder, cross-attention, and language-model head. Use the tokenizer from the loaded model. This keeps tokenizer files, revision, offline/cache policy, and ANKH's residue-aware pre-tokenizer aligned. Pass raw protein strings without residue spaces: ```python import torch tokenizer = model.tokenizer batch = tokenizer( ["MSTNPKPQRKTKRNT", "MKTIIALSYIFCLVFA"], padding=True, return_tensors="pt", ) with torch.inference_mode(): output = model(**batch) print(output.last_hidden_state.shape) ``` ## Dataset embeddings Dataset embeddings use the final encoder state by default. Select a native encoder layer directly: ```python encoder_result = model.embed_dataset( ["MSTNPKPQRKTKRNT"], hidden_state_source="encoder", hidden_state_index=-1, full_embeddings=True, ) print(encoder_result[0].tensor.shape) # (l, d) ``` Decoder representations require `AutoModelForSeq2SeqLM` and one aligned decoder input. ANKH does not create a shifted target: ```python from transformers import AutoModelForSeq2SeqLM seq2seq = AutoModelForSeq2SeqLM.from_pretrained( "Synthyra/ANKH_base", trust_remote_code=True, ).eval() decoder_result = seq2seq.embed_dataset( ["MSTNPKPQRKTKRNT"], hidden_state_source="decoder", hidden_state_index=-1, decoder_inputs=["M"], full_embeddings=True, ) print(decoder_result[0].tensor.shape) # (decoder_length, d) ``` Pooling excludes boundary, padding, sentinel, and other non-biological positions. Persisted results record the selected stack, layer, inputs, masks, and alignment policy. ## Downstream prediction The sequence and token prediction AutoClasses use the checkpoint backbone and create a new, untrained `classifier`. Sequence labels have shape `(b,)`. Residue labels have shape `(b, l)` and use `-100` outside biological positions. ```python import torch from transformers import AutoTokenizer from transformers import ( AutoModelForSequenceClassification, AutoModelForTokenClassification, ) model_id = "Synthyra/ANKH_base" sequence_model = AutoModelForSequenceClassification.from_pretrained( model_id, num_labels=2, trust_remote_code=True ).eval() token_model = AutoModelForTokenClassification.from_pretrained( model_id, num_labels=3, trust_remote_code=True ).eval() tokenizer = AutoTokenizer.from_pretrained(model_id, trust_remote_code=True) sequences = ["MSTNPKPQRKTKRNT", "MKTIIALSYIFCLVFA"] batch = tokenizer(sequences, padding=True, return_tensors="pt") biological = batch["attention_mask"].bool() for special_id in tokenizer.all_special_ids: biological &= batch["input_ids"].ne(special_id) sequence_labels = torch.zeros(len(sequences), dtype=torch.long) token_labels = torch.full_like(batch["input_ids"], -100) token_labels[biological] = 0 with torch.inference_mode(): sequence_output = sequence_model(**batch, labels=sequence_labels) token_output = token_model(**batch, labels=token_labels) print(sequence_output.logits.shape) # (b, 2) print(token_output.logits.shape) # (b, l, 3) ``` ## PEFT fine-tuning Install the training dependencies. Then attach LoRA to the loaded checkpoint: ```bash python -m pip install "datasets>=4.8,<5" "peft>=0.19,<0.20" ``` ```python from peft import LoraConfig, TaskType, get_peft_model peft_model = get_peft_model( sequence_model, LoraConfig( task_type=TaskType.SEQ_CLS, r=8, lora_alpha=16, target_modules="all-linear", modules_to_save=["classifier"], ), ) ``` This checkpoint advertises a classification head. Save the separately trained `classifier` with the adapter. All FastPLMs checkpoints follow the Transformers `PreTrainedModel` contract and can use PEFT. The ESM2-specific shipped CLI is an example, not a support boundary. Record the target modules, base revision, data identity, and trainable parameter scope. ## Test-time training TTT samples masked views of one protein and updates only injected low-rank adapters. Base checkpoint weights stay frozen: ```python from transformers import AutoModelForMaskedLM ttt_model = AutoModelForMaskedLM.from_pretrained( "Synthyra/ANKH_base", trust_remote_code=True, ) metrics = ttt_model.ttt( seq="MSTNPKPQRKTKRNT", ttt_config={"steps": 3, "batch_size": 1, "seed": 7}, ) ttt_model.save_pretrained("adapted", safe_serialization=True) ttt_model.ttt_reset() print(metrics) ``` Saved adapters retain their deterministic reset state. TTT adds latency and memory, can worsen an output, and does not show biological function. ## Encoder and sequence-to-sequence use `Synthyra/ANKH_base` contains the complete ANKH encoder-decoder checkpoint. Use `AutoModel` for encoder embeddings. Use `AutoModelForSeq2SeqLM` for task-specific decoding: ```python import torch from transformers import AutoModel, AutoModelForSeq2SeqLM, AutoTokenizer repo_id = "Synthyra/ANKH_base" tokenizer = AutoTokenizer.from_pretrained(repo_id, trust_remote_code=True) encoder = AutoModel.from_pretrained(repo_id, trust_remote_code=True).eval() seq2seq = AutoModelForSeq2SeqLM.from_pretrained( repo_id, trust_remote_code=True, ).eval() batch = tokenizer("MSTNPKPQRKTKRNT", return_tensors="pt") with torch.inference_mode(): encoder_hidden = encoder(**batch).last_hidden_state generated_ids = seq2seq.generate(**batch, max_new_tokens=16) print(encoder_hidden.shape) print(tokenizer.batch_decode(generated_ids, skip_special_tokens=True)) ``` ANKH artifacts retain CC BY-NC-SA 4.0 terms. The notes below distinguish official heads from FastPLMs extensions. The complete checkpoint is larger than the former encoder-only mirror and preserves encoder-output parity. ## Notes and limitations ANKH parity covers the official encoder and sequence-to-sequence heads. AutoModelForMaskedLM exposes the separately named FastPLMs synthesized masked-LM extension and is not an official ANKH head. ## Technical details - Inputs: Amino-acid sequences tokenized for encoder or sequence-to-sequence use - Transformers classes: `AutoConfig`, `AutoModel`, `AutoModelForMaskedLM`, `AutoModelForSeq2SeqLM`, `AutoModelForSequenceClassification`, `AutoModelForTokenClassification` - Checkpoint weights: `AutoConfig` = `FastPLMs extension`, `AutoModel` = `pretrained`, `AutoModelForMaskedLM` = `FastPLMs extension`, `AutoModelForSeq2SeqLM` = `pretrained`, `AutoModelForSequenceClassification` = `base weights + untrained task head`, `AutoModelForTokenClassification` = `base weights + untrained task head` - Attention backends: `eager`, `sdpa` - Precision: `default` - BF16 execution: `static_parameters` - Generation contract: `required` - Dependencies: `core` - Weight publication allowed: `true` - Weight license status: `resolved` - Redistributable: `true` - Complete weight publication required: `false` ## Validation and provenance FastPLMs pins the checkpoint, upstream source revisions, state transformation, and required files in `models.toml`. Built artifacts record exact source identities and conversion details in `source-record.json`. - FastPLMs checkpoint: `Synthyra/ANKH_base` - Runtime revision: recorded separately in the built artifact and published commit - Runtime source identities: recorded in `source-record.json` - Canonical transformed state identity: recorded in `source-record.json` - Conversion equality attestation: recorded in `source-record.json` - Official checkpoint: `ElnaggarLab/ankh-base` - Artifact source: `official` - State transform: `ankh_t5_to_fastplms_v1` - Pinned upstreams: `ankh` - Release tiers: `check`, `compliance`, `feature`, `artifact`, `benchmark` - Unresolved required file identities: `0` Release validation includes the `compliance` tier. Its evidence identifies the checkpoint, backend, dtype, hardware, inputs, and reference revision. Declared tiers compare configuration, tokenizer behavior, state, and representative inference with the pinned reference. A nonzero unresolved count blocks release. Metadata alone does not show that a build passed, that a backend is faster, or that an output is biologically valid. ## License Checkpoint terms: CC-BY-NC-SA-4.0. The Hub model-card identifier is `cc-by-nc-sa-4.0`. The local artifact contains applicable source licenses, notices, attribution, and conversion records. Review them before use.