vHAMSTeR Models v1.3.0
Model weights for vHAMSTeR (Virus Host Assignment Model using Sequence Transformers and Reading-frames), a tool for predicting the host of a virus from its genomic sequence.
Model description
vHAMSTeR predicts viral host as one of five classes: 'Prokaryote', 'Animal', 'Plant', 'Fungi' or 'Protists, Algae & Oomycetes'.
It is designed for viral sequences up to 10 kbp. Longer sequences are split into 10 kbp chunks, scored independently, and aggregated to produce a genome-level consensus.
Architecture
Each fold in the ensemble consists of:
- PEFT adapter on InstaDeepAI/NTv3_650M_pre β a 650M-parameter nucleotide language model fine-tuned on viral sequences
- XGBoost stacking layer β incorporates geNomad marker features alongside the transformer embeddings
- GLM gate β learned weighting between the transformer and marker feature streams
- Classifier head β produces the final 5-class probability distribution
Predictions are calibrated using length-aware vector scaling (length_aware_vector_scaling_anchors_5.json).
The full ensemble runs 5 cross-validation folds and aggregates their outputs.
Repository structure
vhamster_models_v1.3.0/
βββ length_aware_vector_scaling_anchors_5.json # calibration parameters
βββ fold_0/
β βββ config.json
β βββ best_macro_auprc_model/
β β βββ adapter_config.json
β β βββ adapter_model.safetensors
β β βββ classifier_head.pt
β β βββ tokenizer_config.json
β β βββ tokenization_ntv3.py
β β βββ vocab.json
β βββ xgb_stacking_artifacts/
β βββ xgb_stacking_artifacts.json
β βββ xgb1_binary_model.json
β βββ xgb2_euk_model.json
β βββ marker_classification.pkl
β βββ marker_cutoffs.pkl
βββ fold_1/ β¦ fold_4/ # same structure
Usage
These weights are intended to be used via the vHAMSTeR command-line tool. See the vHAMSTeR repository for full installation instructions.
Model tree for DOEJGI/vhamster-models
Base model
InstaDeepAI/NTv3_650M_pre