┌──────────────────────────────────────────────────────────────────────────────┐
│                                                                              │
│                                                                              │
│                 ██████╗ ███████╗ █████╗ ██╗     ███╗   ███╗                  │
│                 ██╔══██╗██╔════╝██╔══██╗██║     ████╗ ████║                  │
│                 ██████╔╝███████╗███████║██║     ██╔████╔██║                  │
│                 ██╔═══╝ ╚════██║██╔══██║██║     ██║╚██╔╝██║                  │
│                 ██║     ███████║██║  ██║███████╗██║ ╚═╝ ██║                  │
│                 ╚═╝     ╚══════╝╚═╝  ╚═╝╚══════╝╚═╝     ╚═╝                  │
│              Protein Sequence Annotation using a Language Model              │
│                                                                              │
└──────────────────────────────────────────────────────────────────────────────┘

Persistent session mode (load model once, scan many times):

psalm -d auto
# inside shell:
#   scan -f path/to/seqs.fa
#   scan --sort -f path/to/seqs.fa -c 4 --to-tsv hits.tsv
#   scan -s "MSTNPKPQR..."
#   quit

Quick usage:

psalm-scan -f path/to/your_sequence.fasta

CLI behavior notes:

• Default model: ProteinSequenceAnnotation/PSALM-2
• Default device: auto (cuda -> mps -> cpu)
• FASTA scans use fast batched scanning by default
• --serial restores the legacy serial FASTA behavior
• --sort remains opt-in
• -c/--cpu-workers is the number of fast-mode CPU decode helper processes
  • default behavior is equivalent to -c 0
  • if the interactive shell already has warmed workers, later default fast scans reuse that pool
• --max-batch-size controls the fast-mode embedding batch budget in tokens/amino acids
• --max-queue-size controls the fast-mode decode queue in sequences
  • default: 128
• -q/--quiet suppresses scan result output only; startup/status still prints
• --to-tsv and --to-txt work for single or multi-sequence FASTA
• -v/--verbose enables detailed alignment and model tables
  • verbose FASTA scans use the serial path
  • without -v, PSALM prints the compact HITS report
• -T keeps domains with Score >= threshold (default: 0.5)
• -E keeps domains with E-value <= threshold (default: 0.1)
• -Z sets dataset size for E-value scaling
  • if omitted for -s: Z=1
  • if omitted for -f: Z=#sequences in FASTA
• --to-tsv is the supported machine-readable output format

Common shell usage:

psalm
scan --sort -f path/to/seqs.fa --to-tsv hits.tsv

Useful output modes:

# compact terminal report + TSV
scan -f path/to/seqs.fa --to-tsv hits.tsv

# with TSV only
scan -q --sort -f path/to/seqs.fa --to-tsv hits.tsv

# verbose per-domain output
scan -v -f path/to/seqs.fa

For the full option set, run psalm --help, psalm-scan --help, or scan --help.

Installation

Create a fresh Python 3.10 environment, install PyTorch for your hardware, then install PSALM.

conda create -n psalm python=3.10 -y
conda activate psalm
python -m pip install --upgrade pip

# 1) Install PyTorch for your hardware
# Apple Silicon (MPS):
python -m pip install torch

# CPU-only (Linux/Windows):
# python -m pip install torch

# NVIDIA CUDA 12.1:
# python -m pip install --index-url https://download.pytorch.org/whl/cu121 \
#   torch

# 2) Install PSALM
python -m pip install protein-sequence-annotation==2.1.9

If you are unsure which PyTorch command matches your GPU/driver, use the official selector: https://pytorch.org/get-started/locally/

Intel Mac (x86_64) tested path:

conda create -n psalm python=3.10 -y
conda activate psalm

conda install -y -c conda-forge "llvmlite=0.44.*" "numba=0.61.*"
conda install -y -c conda-forge "pytorch=2.5" torchvision torchaudio

python -m pip install protein-sequence-annotation==2.1.9

Optional: run without activating conda manually:

conda run -n psalm psalm-scan -f path/to/seqs.fa

Python API

from psalm.psalm_model import PSALM

psalm = PSALM(model_name="ProteinSequenceAnnotation/PSALM-2")

# Scan FASTA
results = psalm.scan(fasta="path/to/your_sequence.fasta")
print(results)

# Scan sequence string
results = psalm.scan(sequence="MSTNPKPQR...AA")

Output options:

• to_tsv="results.tsv" writes: Sequence,E-value,Score,Pfam,Start,Stop,Model,Len Frac,Status
• to_txt="results.txt" saves console-style output
• For multi-sequence FASTA, TSV rows are combined with the query id in the Sequence column

Scripts overview

The core workflow is:

1. scripts/data/augment_fasta.py → slice sequences and generate augmented FASTA + domain dict
2. scripts/data/data_processing.py → tokenize, label, batch, and shard datasets
3. scripts/train/train_psalm.py → train/evaluate the PSALM model on shards

scripts/data/augment_fasta.py

Splits long sequences into domain-preserving slices and optionally emits shuffled and negative variants. Produces a new FASTA and a new domain dict with aligned IDs.

Key inputs

• --fasta, --domain-dict
• --output-fasta, --output-dict

Common flags

• --max-length: slice length threshold
• --negative-prob: target fraction of negatives (approximate)
• --include-domain-slices, --shuffle-only, --no-shuffle, --domain-slices-only
• --large-data with --p-shuffled, --domain-counts-tsv, --domain-slice-frac
• --seed, --verbose

scripts/data/data_processing.py

Tokenizes sequences, generates per-token labels from the domain dict and label mapping, batches by token budget, and saves shards.

Config handling

• This script is CLI-only; it does not read config.yaml.

Required args

• --fasta, --domain-dict, --output-dir, --ignore-label
• --model-name, --max-length, --max-tokens-per-batch
• --label-mapping-dict

Optional args

• --chunk-size, --tmp-dir, --shard-size, --seed, --keep-tmp

Notes

• ID normalization uses the FASTA header segment between > and the first space.
• --ignore-label must match the training --ignore-label.

scripts/train/train_psalm.py

Trains or evaluates PSALM on preprocessed shard datasets.

Config handling

• Training always uses a YAML config.
• If --config is provided without a value, the script looks for psalm/config.yaml.
• If --config is not provided, the script still looks for psalm/config.yaml.

Required args

• --val-dir, --ignore-label
• --train-dir if training.total_steps > 0 in config

Optional args

• --label-mapping-dict to override config model.label_mapping_path

Checkpoint loading

• Supports model.safetensors or pytorch_model.bin within a checkpoint directory, or a direct path to a .safetensors/.bin file.

Logging

• report_to=["wandb"] is enabled by default.

scripts/train/train_cbm.py

Trains the CatBoost scoring model used by scan() (saved as score.cbm).

Required args

• --pos, --neg: Pickle or JSON files containing a list of 7-tuples: (pfam, start, stop, bit_score, len_ratio, bias, status) (or scan() output dicts containing 8-tuples with cbm_score).

Example

python scripts/train/train_cbm.py \
  --pos path/to/positives.pkl \
  --neg path/to/negatives.pkl \
  --outdir cbm_outputs \
  --model-out score.cbm

Config format

The scripts expect a YAML config with these sections:

model

• model_name
• max_batch_size
• output_size
• freeze_esm
• use_fa
• pretrained_checkpoint_path
• label_mapping_path

training

• gradient_accumulation_steps, learning_rate, optimizer, gradient_clipping
• lr_scheduler, eval_strategy, eval_steps, total_steps, warmup_steps
• logging_steps, save_steps, output_dir
• mixed_precision, dataloader_num_workers, dataloader_prefetch_factor, dataloader_pin_memory, seed

data

• chunk_size, default_tmp_dir, default_shard_size

psalm/config.yaml is provided as a template with null values. Populate it before use, or pass all required values via CLI without --config.

Training CLI examples

python scripts/data/augment_fasta.py \
  --fasta input.fa \
  --domain-dict domains.pkl \
  --output-fasta augmented.fa \
  --output-dict augmented.pkl

python scripts/data/data_processing.py \
  --fasta augmented.fa \
  --domain-dict augmented.pkl \
  --label-mapping-dict labels.pkl \
  --output-dir data/shards \
  --model-name ProteinSequenceAnnotation/esm2_t33_650M_PFS90_leaky \
  --max-length 4096 \
  --max-tokens-per-batch 8196 \
  --ignore-label -100

python scripts/train/train_psalm.py \
  --config psalm/config.yaml \
  --train-dir data/shards/train \
  --val-dir data/shards/val \
  --ignore-label -100

Dependencies

• PyYAML is required for config loading.
• faesm is required only if use_fa: true in config.
• Core inference runtime uses torch, transformers, biopython, pandas, numba, and catboost.