Update README.md

README.md

@@ -18,4 +18,17 @@ task_categories:
 - text2text-generation
 - translation
 task_ids: []
----
+---
+
+### dataset description
+We downloaded open-reaction-database(ORD) dataset from [here](https://github.com/open-reaction-database/ord-data). As a preprocess, we removed overlapping data and canonicalized them using RDKit.
+We used the following function to canonicalize the data and removed some SMILES that cannot be read by RDKit.
+    
+```python:
+from rdkit import Chem
+def canonicalize(mol):
+    mol = Chem.MolToSmiles(Chem.MolFromSmiles(mol),True)
+    return mol 
+```
+
+We randomly split the preprocessed data into train, validation and test. The ratio is 8:1:1.