Computational graph-based network models

This open-source aims to construct transportation network models using computational graphs and find optimal solutions based on the automatic differentiation algorithm (TensorFlow 2.0).

1. The computational graph-based recursive logit model is coded based on "Fosgerau, M., Frejinger, E. and Karlstrom, A., 2013. A link based network route choice model with unrestricted choice set. Transportation Research Part B: Methodological, 56, pp.70-80."
2. CG-based OD estimation model is referred from "Wu, X., Guo, J., Xian, K. and Zhou, X., 2018. Hierarchical travel demand estimation using multiple data sources: A forward and backward propagation algorithmic framework on a layered computational graph. Transportation Research Part C: Emerging Technologies, 96, pp.321-346."