Mizan-Rerank-v3

A compact, fast Arabic reranker that tells the passage that answers the question apart from passages that only look like they do.

The Mizan reranker family

Model	Parameters	Throughput	Held-out mean nDCG@10	Fiqh nDCG@10
Mizan-Rerank-v3-Turbo	150M	2,487 pairs/s	0.875	0.761
Mizan-Rerank-v3 (this model)	306M	1,238 pairs/s	0.826	0.669

Pick Turbo for the best accuracy per millisecond; v3 is the larger model with the same behaviour as this release.

Held-out mean nDCG@10 is the mean over the four held-out sets both cards share (NamaaMrTydi unseen, short adversarial, long-context adversarial, Multi-LLM), so it reads 0.826 here while the table below quotes 0.845 over five sets: that figure additionally averages the Arabic Hard Negatives unseen subset, which Turbo cannot use because only 10 of its 12,373 cases are unseen for it.

Mizan-Rerank-v3 is a 306M-parameter Arabic cross-encoder. It was fine-tuned from Alibaba-NLP/gte-multilingual-reranker-base on 71k Arabic listwise groups. Each group pairs the correct passage with adversarial "trap" passages that share most of its words but change its meaning: a negated ruling, a swapped entity, a shifted number or date, an exception applied to the wrong case.

The result is a small model with the accuracy of a much larger one. It has about half the parameters of bge-reranker-v2-m3 (568M) and scores twice as many query–passage pairs per second, yet it ranks higher on average across our held-out Arabic benchmarks. It is built for Arabic search and RAG pipelines, especially over long, dense religious and encyclopedic text, where reranking latency matters.

Highlights

• Accurate for its size. Held-out mean nDCG@10 is 0.845 at 306M parameters. The 568M bge-reranker-v2-m3 scores 0.802, the gte base 0.783 and Mizan-Rerank-V2 0.723.
• Fast. On one RTX 4090 in fp16 it scores 1,228 pairs/s, 2.0× bge-reranker-v2-m3's 600 pairs/s, with 23% less peak GPU memory (see Efficiency).
• Picks the right passage first. Hit@1 on held-out long-context adversarial queries is 0.570, vs 0.336 for bge-reranker-v2-m3, 0.314 for gte base and 0.227 for Mizan-Rerank-V2.
• Rarely puts a contradiction on top. Across 2,666 held-out adversarial queries, the top-ranked passage is a contradicting trap 32.5% of the time. For bge-reranker-v2-m3 the figure is 56.8%; for Mizan-Rerank-V2, 73.0%.
• A drop-in upgrade over Mizan-Rerank-V2. It has the same architecture, size and speed, and scores higher on every benchmark.

Usage

Sentence Transformers

pip install -U sentence-transformers

from sentence_transformers import CrossEncoder

model = CrossEncoder("ALJIACHI/Mizan-Rerank-v3", trust_remote_code=True, max_length=3072)

query = "ما هي فوائد فيتامين د؟"
passages = [
    "يساعد فيتامين د على امتصاص الكالسيوم وتقوية العظام، كما يدعم عمل الجهاز المناعي.",
    "يستخدم فيتامين د في بعض الصناعات الغذائية كمادة مضافة لتدعيم الحليب.",
    "أطلقت وزارة الزراعة حملة وطنية لزيادة الوعي بأهمية الزراعة العضوية.",
]

scores = model.predict([(query, passage) for passage in passages])
print(scores)  # ≈ [0.875, 0.023, 0.010]  (sigmoid relevance scores)

for hit in model.rank(query, passages, return_documents=True):
    print(f"{hit['score']:.3f}  {hit['text']}")

Transformers

import torch
from transformers import AutoModelForSequenceClassification, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained("ALJIACHI/Mizan-Rerank-v3")
model = AutoModelForSequenceClassification.from_pretrained(
    "ALJIACHI/Mizan-Rerank-v3", trust_remote_code=True, torch_dtype=torch.float16
).to("cuda").eval()

query = "ما هي فوائد فيتامين د؟"
passages = [
    "يساعد فيتامين د على امتصاص الكالسيوم وتقوية العظام، كما يدعم عمل الجهاز المناعي.",
    "أطلقت وزارة الزراعة حملة وطنية لزيادة الوعي بأهمية الزراعة العضوية.",
]

with torch.inference_mode():
    features = tokenizer([query] * len(passages), passages, padding=True, truncation=True,
                         max_length=3072, return_tensors="pt").to("cuda")
    scores = torch.sigmoid(model(**features).logits.squeeze(-1).float())

for passage, score in sorted(zip(passages, scores.tolist()), key=lambda item: -item[1]):
    print(f"{score:.3f}  {passage}")

Practical notes

• Sequence length. The model was trained on query + passage inputs of up to 3,072 tokens and is benchmarked here at 2,048. The architecture accepts 8,192 positions, but quality beyond 3,072 tokens has not been measured. If your query + passage inputs fit in 512 tokens, max_length=512 is much faster.
• Scores. The sigmoid of the single output logit is a relevance score. It works for ranking and for coarse cut-offs, but it is not a calibrated probability: tune any threshold on your own data.
• trust_remote_code=True is required. The architecture code (modeling.py, configuration.py) comes from the gte base model and ships in this repository.

Evaluation

All four models were scored by the same script (benchmark/benchmark_rerankers.py) with the same inputs: float32, max_length=2048, and the full candidate list of every query. Metrics use graded gains (correct passage 3, partially correct passage 1, trap or irrelevant passage 0).

Held-out benchmarks

¹ Queries whose question and correct passage never occur in the v3 training pool (hashes in benchmark/seen_in_training.json). ² Internal test sets, not released. They share no queries or passages with the training data (verified by exact match), and the long-context split is by source article.

Where the gain comes from: ranking the correct passage first. Hit@1 is where v3 differs most from the other models, especially when traps share most of their text with the answer:

Contradiction ranked first

For RAG the worst failure is not a missing answer but a passage that says the opposite ranked at the top: a negated ruling, a reversed condition, a wrong number. Every adversarial test query has one correct passage and several contradicting traps. The table shows how often a trap was ranked #1 (lower is better):

Across all 2,666 queries, v3 ranks a trap first 32.5% of the time. For bge-reranker-v2-m3 the figure is 56.8%; for gte base, 63.8%; for Mizan-Rerank-V2, 73.0%:

Reproduce with python compare_generated_test_models.py --dataset-file <test.jsonl> ... --chart contradiction_first.png (in the training repository; the test sets are internal).

nDCG@10

MRR@10

Hit@1

³ 97% of these queries occur in the v3 training pool, so the full-set score is not a fair measure for v3 and is not bolded or used in any average.

Efficiency

Every model scored the same 2,048 Arabic query–passage pairs from MTEB NamaaMrTydi. The run used one NVIDIA RTX 4090, float16, batch size 32 and max_length=512, after a warm-up (benchmark/speed_benchmark.py):

At the same latency budget, v3 can rerank twice as many candidates as bge-reranker-v2-m3. It reaches the highest held-out accuracy of the four models while running at the speed of the smallest.

Training

Data (71,044 listwise groups)

Every group is one query with one correct passage, up to 5 hard negatives and, for adversarial groups, one partially correct passage.

The adversarial negatives cover 12 trap types, each a minimal edit that changes the meaning while keeping most of the words: negation_flip, exception_scope, entity_role_reversal, entity_swap, ordered_precedence, temporal_boundary, numeric_boundary, quantifier_change, causal_direction, condition_swap, conclusion_flip, attribution_shift.

Leakage controls: the adversarial train, validation and test splits are split by source article. Extra training data sharing a source article or a query with any validation or test set was removed. The three legacy sources were additionally filtered against every evaluation set by 8-word shingles. All held-out sets above were re-checked against the final training pool by exact query and passage match.

Objective

For each group the model scores all candidates jointly:

• Pointwise: binary cross-entropy, targets 1 / 0.5 / 0 for correct / partial / negative, pos_weight=1.24, weight 0.5.
• Pairwise: softplus margin loss softplus(s_neg − s_pos + 0.2) for every negative, weight 1.0.
• Partial order: the same margin loss for correct > partial > negative, weight 0.5 within the pairwise term.

Configuration

Framework versions

Python 3.10.14 · PyTorch 2.8.0+cu126 · Transformers 4.55.4 · Sentence Transformers 5.4.1 · Accelerate 1.10.0 · Tokenizers 0.21.0

Citation

@software{Mizan_Rerank_v3_2026,
  author    = {Ali Aljiachi},
  title     = {Mizan-Rerank-v3: Adversarially Trained Arabic Long-Context Reranker},
  year      = {2026},
  publisher = {Hugging Face},
  url       = {https://huggingface.co/ALJIACHI/Mizan-Rerank-v3}
}

License

Apache 2.0, the same license as the base model Alibaba-NLP/gte-multilingual-reranker-base.