Chen-Robien algorithm

Various atom and/or bond properties can also be used to cut off some bad branches, even to completely cut down some fruitless trees. The Chen Robien algorithm allows the user to decide whether these additional conditions should be taken into account during the matching process. However, as Chen and Robien [1] have demonstrated, the actual decision on using these conditions depends on the application. 

The combination of the new methods for optimizing and pruning search trees described above, and the backtracking technique, makes the Chen-Robien algorithm a very fast MCSS algorithm. It has become a central mainstay of several other commands within the CSEARCH-NMR database system [69]. 

It is obvious that trying to explore all possibilities is too time-consuming except for small structures only. The high efficiency of the Chen-Robien MCSS algorithm [1] is achieved by using several new strategies to reduce the search space, which will be described below. 

Chen L, Robien W. MCSS a new algorithm for perception of maximal common substructures and its application to NMR spectral studies. 1. The algorithm. J Chem Inf Comput Sci 1992 32 501-506. 

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