Add vONTSS

[jiangxiaoyuwww]

Tested via dataset loaded via load_dataset

from datasets import load_dataset
from octis.evaluation_metrics.diversity_metrics import TopicDiversity
from octis.evaluation_metrics.coherence_metrics import Coherence
from octis.models.VONT import VONT


df = load_dataset('xwjzds/ag_news')
model_output = model.train_model(df['train']['text'])# Train the model

TODO: change dataset proprocessing function to take OCTIS's dataset format as input