spacy-fa-pipeline/README.md

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Persian (Farsi) pipelines for spaCy

Trained spaCy pipelines for Persian, installable now. spaCy has never shipped an official one, and spacy.blank("fa") only gives you a tokenizer and stop words. Choose between fa_core_news_sm (full syntax + NER) or fa_dep_news_sm (syntax only).

pip install https://huggingface.co/Phazel/fa_core_news_sm/resolve/main/fa_core_news_sm-3.8.0-py3-none-any.whl
>>> import spacy
>>> nlp = spacy.load("fa_core_news_sm")

>>> doc = nlp("محمدرضا شجریان در مشهد به دنیا آمد.")
>>> [(t.text, t.pos_, t.lemma_, t.dep_) for t in doc][:2]
[('محمدرضا', 'PROPN', 'محمدرضا', 'nsubj'), ('شجریان', 'PROPN', 'شجریان', 'flat:name')]
>>> doc.ents
(محمدرضا شجریان, مشهد)

>>> doc = nlp("شرکت ایران خودرو تولید را ۲۰ درصد افزایش می‌دهد.")
>>> [(e.text, e.label_) for e in doc.ents]
[('ایران خودرو', 'ORG'), ('۲۰ درصد', 'PCT')]

Results

Compared against Hazm (the most-used Persian toolkit) and en_core_web_sm (English reference).

Metric spacy-persian
fa_core_news_trf
Hazm
(Persian toolkit)
en_core_web_sm
(English reference)
POS Accuracy (UPOS) 97.63% ~95.69%¹ 97.21%²
Lemma Accuracy 97.31% 89.9%¹
Dependency LAS 90.79% 85.6%¹ 91.85%²
NER F-score 82.89% 83.80%²

¹ Hazm scores from its official README ² en_core_web_sm scores from spaCy's official model card

Note on comparability: These benchmarks come from different evaluation sets, treebanks, and test splits.

From spacy benchmark accuracy, stored in metrics/.

Package Components Licence Score Wheel
fa_dep_news_sm tok2vec, tagger, morphologizer, trainable_lemmatizer, parser CC BY-SA 4.0 LEMMA 97.91 7.9 MB
fa_core_news_sm the above plus ner CC BY-SA 4.0 ENTS_F 71.87 13.5 MB
fa_ent_news_sm ner alone (own embedded tok2vec) CC BY-SA 4.0 ENTS_F 71.87 5.9 MB
fa_dep_news_md same as fa_dep_news_sm, plus floret vectors CC BY-SA 4.0 LEMMA 97.96 62.6 MB
fa_core_news_md same as fa_core_news_sm, plus floret vectors CC BY-SA 4.0 ENTS_F 74.71 68.5 MB
fa_ent_news_md ner alone (own embedded tok2vec), plus floret vectors CC BY-SA 4.0 ENTS_F 74.71 60.6 MB
fa_dep_news_lg same as fa_dep_news_sm, plus full-wiki floret vectors CC BY-SA 4.0 LEMMA 98.08 229.3 MB
fa_core_news_lg same as fa_core_news_sm, plus full-wiki floret vectors CC BY-SA 4.0 ENTS_F 75.94 235.2 MB
fa_ent_news_lg ner alone (own embedded tok2vec), plus full-wiki floret vectors CC BY-SA 4.0 ENTS_F 75.94 227.3 MB
fa_core_news_trf transformer, tagger, morphologizer, trainable_lemmatizer, parser, ner see §8, encoder unlicensed ENTS_F 82.89, LAS 90.79 608.2 MB

Standalone floret vector packages: fa_floret_400k, fa_floret_full_wiki.

The md tier adds a 50k x 300d floret vector table trained on 400k Persian documents. Its config differs from sm by exactly one line (include_static_vectors), so the columns below isolate what the vectors buy. Full breakdown in docs/MODELS.md §6.

Metric sm md lg trf Reference
TOKEN_ACC / TOKEN_F 99.96 / 99.11 99.96 / 99.11 99.96 / 99.11 99.96 / 99.11
TAG_ACC (XPOS) 95.96 96.25 96.55 97.62
POS_ACC (UPOS) 96.24 96.64 96.68 97.63
MORPH_ACC 96.29 96.64 96.70 97.82
LEMMA_ACC 97.91 97.96 98.08 97.31
SENTS_F 99.25 99.28 99.18 97.35
DEP_UAS 89.69 90.52 90.96 93.87 hazm+ParsBERT: 92.46
DEP_LAS 85.15 86.34 86.60 90.79 hazm+ParsBERT: 89.34
ENTS_P 77.67 76.56 81.51 84.06
ENTS_R 66.87 72.95 71.09 81.76
ENTS_F 71.87 74.71 75.94 82.89
Speed (940MX, batch 32) 10,235 words/s 9,058 words/s 9,215 words/s see §Throughput
Wheel size 13.5 MB 68.5 MB 235 MB 608 MB

trf leads everywhere except lemmatization and sentence segmentation, and is the only tier to pass the hazm+ParsBERT DEP_LAS reference of 89.34. It needs a GPU, and its encoder states no licence so it is not redistributable (docs/MODELS.md §8).

Entity scores are fa_core_news_* on the PerDT NER test split; per-label breakdown and caveats are in Named entity recognition.

For comparison, en_core_web_sm scores TAG 97, LAS 90, ENTS_F 84 on a larger, cleaner corpus. Trained on a 4-core i5-7200U with no GPU: sm 1h27m syntax + 17 min NER, md 1h54m syntax

  • 25 min NER (the two md runs overlapped, so wall clock overstates each).

Throughput

Median of repeated nlp.pipe passes over the 146-document PerDT test split (23,825 tokens), timing the pipe only, warmup discarded. Reproduce with python scripts/benchmark_throughput.py <model> --gpu-id <n>; raw records are in metrics/throughput-*.json.

Tier CPU, i5-7200U GPU, GeForce 940MX GPU, Tesla T4
sm 5,484 10,235
md 5,408 9,058
lg 4,715 9,215
trf 187 1,106 8,320

trf is 29x slower than sm on the same CPU. The T4 and Xeon figures come from one Colab VM, a 25x GPU speedup. The CPU tiers sit within 15% of each other, so the bottleneck is the parser and lemmatizer, not the tok2vec lookup. Laptop spread is about 10% with thermal state. Running trf on the 940MX needs a specific torch build, see docs/MODELS.md §9.

Named entity recognition

Seven labels: LOC, PER, ORG, DAT, MON, TIM, PCT. They come from PerDT's own not-to-release/Dadegan with NER tag/ layer, transferred onto this pipeline's tokenization by difflib at a 99.86% alignment rate; spans that could not be aligned exactly were dropped rather than guessed (scripts/transfer_perdt_ner.py). That layer is silver: PerDT's README states it was produced by the BERT-based Beheshti-NER tagger with manual corrections for recall, so the ENTS_F numbers below partly reflect agreement with that tagger, not with human annotation.

ner runs standalone with its own embedded tok2vec (fa_ent_news_sm, fa_ent_news_md), or bundled into fa_core_news_sm/fa_core_news_md alongside the syntax pipeline. In trf it is trained jointly against the shared transformer instead, so there is no standalone trf variant.

Label sm F md F lg F trf F Train examples
LOC 80.24 84.05 83.66 87.78 4,954
PER 65.29 68.18 72.63 81.88 4,847
ORG 68.77 70.25 71.01 78.50 2,643
DAT 74.45 76.19 70.83 82.52 1,323
MON 73.68 84.21 88.89 88.89 205
TIM 66.67 66.67 61.54 50.00 135
PCT 57.14 33.33 57.14 33.33 121

MON, TIM and PCT have single-digit support in the test split, so their deltas are one or two entities changing hands, not signal. PER, LOC and ORG carry the split. The md gain over sm (ENTS_F 71.87 to 74.71) is almost entirely recall (+6.08), the lexical prior static vectors give rare proper nouns that hash embeddings never had. trf adds another +6.95 F over lg, again mostly recall (71.09 to 81.76), and its largest per-label gains are PER (+9.25) and DAT (+11.69).

Install

pip install https://huggingface.co/Phazel/fa_core_news_sm/resolve/main/fa_core_news_sm-3.8.0-py3-none-any.whl
# or, without NER:
pip install https://huggingface.co/Phazel/fa_dep_news_sm/resolve/main/fa_dep_news_sm-3.8.0-py3-none-any.whl

Caveats

  • Some lemmas contain a space. Multiword tokens were merged, so کتاب‌هایش is one token tagged N_IANM_PR_JOPER with lemma کتاب او. This affects about 1.5% of tokens.
  • doc.noun_chunks under-fires. spacy/lang/fa/syntax_iterators.py upstream matches ClearNLP labels that do not exist in Universal Dependencies. Patch in docs/upstream/fa-noun-chunks.md.

Build

Everything is reproducible from checksummed assets. Python 3.12:

python -m venv .venv
.venv/bin/python -m pip install -U pip
.venv/bin/python -m pip install "spacy>=3.8,<3.9" spacy-lookups-data

.venv/bin/python -m spacy project assets      # download + checksum the corpora
.venv/bin/python -m spacy project run all     # -> fa_dep_news_sm + fa_core_news_sm
.venv/bin/python -m spacy project run ent     # -> fa_ent_news_sm, NER alone
Command What it does
inspect annotation coverage of the treebanks (scripts/inspect_treebanks.py)
convert-ud CoNLL-U to DocBin with --merge-subtokens, plus the tokenizer-agreement report
transfer-ner align PerDT's NER layer onto that tokenization by difflib (scripts/transfer_perdt_ner.py)
convert-ner transferred IOB2 to DocBin
debug-data, debug-data-ner spacy debug data on both corpora before spending CPU
train-dep tagger + morphologizer + trainable_lemmatizer + parser
train-ner the ner component, with its own embedded tok2vec
finalize-dep write fa_dep_news_sm metadata: sources, licence, notes (scripts/finalize_pipeline.py)
evaluate-dep spacy benchmark accuracy on the held-out UD test split
assemble-core source ner into the dep pipeline to produce fa_core_news_sm
evaluate-core score the assembled pipeline on both test splits
finalize-meta re-run finalize on both, folding test scores into meta.json["performance"]
package build wheels + sdists for both
smoke run both pipelines over Persian text and print every annotation layer

The two training runs are single-threaded and independent, so they can run concurrently.

Design decisions

  1. --merge-subtokens. spaCy has no multiword-token layer, and PerDT splits pronominal clitics (پدرم into پدر + م). Measured on dev, merging gives token F 0.9887 against 0.9823 for the split version, costing 34 composite XPOS tags on 1.5% of tokens. Without it, 1.5% of gold tokens are boundaries the shipped tokenizer can never produce. See scripts/tokenization_report.py.
  2. ner carries its own tok2vec. A Tok2VecListener only resolves inside the pipeline it was trained in, so a listener-based component cannot be sourced elsewhere. configs/fa_ner_sm.cfg embeds the tok2vec instead, as en_core_web_sm does.
  3. morphologizer + trainable_lemmatizer instead of attribute_ruler + rule lemmatizer. The English pipelines derive UPOS from PTB tags by rule because OntoNotes has no UPOS. UD gives gold UPOS, FEATS and lemmas, which yields real pos_acc, morph_acc and lemma_acc numbers instead of unmeasurable rule coverage.
  4. PerDT, not Seraji: 3.7x more tokens, and Seraji has no PROPN tag.

Why not hazm's own models

hazm is the reference Persian NLP toolkit and publishes spaCy-format pipelines on the HF Hub, so it was the obvious starting point. Four problems:

  • Its trainable models are pycrfsuite CRFs (hazm/sequence_tagger.py). The repo contains no config.cfg and no spacy train; the Spacy* classes only download pretrained pipelines.
  • Those pipelines are three single-task models (transformer + tagger, transformer + parser, transformer + chunker), each version: 0.0.0 with an empty license field, pinned to spaCy 3.6. Using all three costs three ParsBERT forward passes and gives no shared Doc.
  • Its tokenizer is incompatible with UD tokenization: the normaliser fuses ZWNJ affixes and join_verb_parts() glues multi-word verb chains into single tokens.
  • Most corpora it reads (Bijankhan, Peykare, Hamshahri, raw PerDT) sit behind peykaregan.ir or dadegan.ir under research-only terms.

It did confirm the corpus choice. hazm's own spaCy parser was trained on modified_fa_perdt-ud-train.spacy, the same treebank used here.

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