The pre-trained model for bidirectional RNNs is consistent with the non-univocal nature of SMILES coding. Although most of the time we choose the standard SMILES encoding for the application, the molecule itself does not have a starting point and direction, i.e., the SMILES encoding can be written in any direction starting from any non-hydrogen atom. Therefore, it is more beneficial to generate molecules with a non-directional CNSMolGen model when performing deep learning .