“…They have widely been applied to fields particularly computer vision, speech recognition, natural language processing, audio recognition, social network filtering, machine translation, bioinformatics, and various games (Collobert and Weston, 2008;Bengio, 2009;Dahl et al, 2012;Hinton et al, 2012;LeCun et al, 2015;Defferrard et al, 2016;Mamoshina et al, 2016), where they have produced results comparable to or in some cases superior to human experts. In recent years, deep learning has also been applied to drug discovery, and it has demonstrated its potentials (Lusci et al, 2013;Ma et al, 2015;Xu et al, 2015;Aliper et al, 2016;Mayr et al, 2016;Pereira et al, 2016;Subramanian et al, 2016;Kadurin et al, 2017;Ragoza et al, 2017;Ramsundar et al, 2017;Xu et al, 2017;Ghasemi et al, 2018;Harel and Radinsky, 2018;Hu et al, 2018;Popova et al, 2018;Preuer et al, 2018;Russo et al, 2018;Segler et al, 2018;Shin et al, 2018;Cai et al, 2019;Wang et al, 2019a;Yang et al, 2019). However, there are still some issues that limit the application of deep learning in drug discovery.…”