🐛 [Metrics] ROUGE is non-deterministic
> If I run the ROUGE metric 2 times, with same predictions / references, the scores are slightly different.
> 
> Refer to [this Colab notebook](https://colab.research.google.com/drive/1wRssNXgb9ldcp4ulwj-hMJn0ywhDOiDy?usp=sharing) for reproducing the problem.
> 
> Example of F-score for ROUGE-1, ROUGE-2, ROUGE-L in 2 differents run :
> 
> > ['0.3350', '0.1470', '0.2329']
> > ['0.3358', '0.1451', '0.2332']
> 
> Why ROUGE is not deterministic ?

This is because of rouge's `BootstrapAggregator` that uses sampling to get confidence intervals (low, mid, high).
You can get deterministic scores per sentence pair by using
```python
score = rouge.compute(rouge_types=["rouge1", "rouge2", "rougeL"], use_agregator=False)
```
Or you can set numpy's random seed if you still want to use the aggregator.
If I run the ROUGE metric 2 times, with same predictions / references, the scores are slightly different.

Refer to [this Colab notebook](https://colab.research.google.com/drive/1wRssNXgb9ldcp4ulwj-hMJn0ywhDOiDy?usp=sharing) for reproducing the problem.

Example of F-score for ROUGE-1, ROUGE-2, ROUGE-L in 2 differents run :

> ['0.3350', '0.1470', '0.2329']
['0.3358', '0.1451', '0.2332']

---

Why ROUGE is not deterministic ?
🐛 [Metrics] ROUGE is non-deterministic 
 If I run the ROUGE metric 2 times, with same predictions / references, the scores are slightly different.

Refer to [this Colab notebook](https://colab.research.google.com/drive/1wRssNXgb9ldcp4ulwj-hMJn0ywhDOiDy?usp=sharing) for reproducing the problem.

Example of F-score for ROUGE-1, ROUGE-2, ROUGE-L in 2 differents run :

> ['0.3350', '0.1470', '0.2329']
['0.3358', '0.1451', '0.2332']

---

Why ROUGE is not deterministic ? 
 > If I run the ROUGE metric 2 times, with same predictions / references, the scores are slightly different.
> 
> Refer to [this Colab notebook](https://colab.research.google.com/drive/1wRssNXgb9ldcp4ulwj-hMJn0ywhDOiDy?usp=sharing) for reproducing the problem.
> 
> Example of F-score for ROUGE-1, ROUGE-2, ROUGE-L in 2 differents run :
> 
> > ['0.3350', '0.1470', '0.2329']
> > ['0.3358', '0.1451', '0.2332']
> 
> Why ROUGE is not deterministic ?

This is because of rouge's `BootstrapAggregator` that uses sampling to get confidence intervals (low, mid, high).
You can get deterministic scores per sentence pair by using
```python
score = rouge.compute(rouge_types=["rouge1", "rouge2", "rougeL"], use_agregator=False)
```
Or you can set numpy's random seed if you still want to use the aggregator.