https://github.com/ethz-asl/grid_map
Loop Closure Detection for Large-Scale Multi-Session Graph-Based SLAM (RGB-D Graph SLAM) ros enabled https://github.com/introlab/rtabmap
https://research.cc.gatech.edu/borg/download?destination=node%2F299 using factor graphs and Bayes networks as the underlying computing paradigm rather than sparse matrices. and matlab also included in it