opus-mt-hy-en-onnx

ONNX export (fp32 + dynamic int8) of Helsinki-NLP/opus-mt-hy-en, a Marian (hy -> en) translation model from the Helsinki-NLP OPUS-MT project.

License: apache-2.0, inherited unchanged from the base model.

Contents

Files	What it is
encoder_model.onnx, decoder_model.onnx, decoder_with_past_model.onnx	ONNX, float32
int8/	same three graphs, dynamic int8 (QInt8, MatMul only, /lm_head/MatMul excluded)
source.spm, target.spm, vocab.json	MarianTokenizer over the original sentencepiece models

fp32 size: 868 MB (three graphs) | int8 size: 679 MB

Usage

from optimum.onnxruntime import ORTModelForSeq2SeqLM
from transformers import AutoTokenizer

repo = "TigreGotico/opus-mt-hy-en-onnx"
tok = AutoTokenizer.from_pretrained(repo)
model = ORTModelForSeq2SeqLM.from_pretrained(repo, use_cache=True, use_merged=False)  # fp32
# int8: ORTModelForSeq2SeqLM.from_pretrained(repo, subfolder="int8", use_cache=True, use_merged=False)
inputs = tok("Այսօր եղանակը շատ գեղեցիկ է:", return_tensors="pt")
out = model.generate(**inputs, num_beams=4, max_new_tokens=64)
print(tok.decode(out[0], skip_special_tokens=True))

Parity with the original PyTorch model

10 general-domain Armenian sentences (source language for this hy->en pair), exact-string-match of generated output against MarianMTModel.generate() on the original Helsinki-NLP/opus-mt-hy-en checkpoint.

parity:
  fp32_greedy: 1.00   # 10/10
  fp32_beam4:  1.00   # 10/10
  int8_greedy: 1.00   # 10/10
  int8_beam4:  0.90   # 9/10

Decoding	fp32 exact match	int8 exact match
greedy (num_beams=1)	10/10 (100.0%)	10/10 (100.0%)
beam=4	10/10 (100.0%)	9/10 (90.0%)

fp32 is an exact reproduction of the original model at both decoding settings, and int8 matches it almost everywhere - the best int8 agreement observed among the Armenian/Azerbaijani models converted in this batch. The single beam=4 disagreement was inspected by hand: ref "Can you help me find the next train station?" vs int8 "Can you help me find my nearby railway station?" - a paraphrase, not a degradation.

An earlier version of this card reported int8 80%/90% from a harness bug - the parity script had reused a fixed English sentence set across all opus-mt pairs, but this model's source language is Armenian, not English, so that measurement compared the model against out-of-distribution input and was discarded. The numbers above are the corrected, re-measured values using real Armenian source sentences.