Export in different formats

[Simrut]

• Knowledge Graph Export From Elasticsearch #106
• Parquet export of SERPs (+ export to HF datasets)
• Parquet export of results (+ export to HF datasets)
• TREC-style export as:
  • topics based on SERP queries
  • qrels based on rank on SERP (e.g., relevance label 10 for rank 1 and label 1 for rank 10)
  • documents (JSONL file with main texts of results)

[janheinrichmerker]

One other thing, we might want to consider in the exports:
The AQL has many duplicates, which we could merge in the export (if that is desirable)