The generation procedure of ECFP can be divided into the following steps (Rogers and Hahn, 2010). (1) Initial assignment of the atom identifiers. The initial integer identifiers, which are assigned to all the non-hydrogen atoms of the given molecule, encode the local information about the corresponding atom such as Sybyl atom type, atomic number, and connection count etc. (2) Iterative update of the atom identifiers. Each atom identifier is recursively updated to reflect the identifiers of each atom's neighbors till a specified diameter is reached. The commonly defined diameter is 4 or 6. (3) Duplication elimination of the atom identifiers. The multiple identifiers representing the equivalent atom-environment are removed. (4) Folding operation of the atom identifiers. All the identifiers are mapped into the bit string with the fix-sized length, in spite of the occasional bit collision. The frequently-used length of the fingerprint is 1,024 or 2,048 bits. (5) Record of the structural features. Finally all the fingerprint bits “1,” original identifiers and their corresponding structural features are recorded for the subsequent visualization. This step is purposely designed to couple with our 3D visualization platform. In this study, 1024bit-ECFP4, 2048bit-ECFP4, 1024bit-ECFP6, and 2048bit-ECFP6 will be harnessed in the following model-training, since more bits will reduce the chance of bit collision during the folding operation, while the larger diameters will provide more structural features.