An Efficient Algorithm for Automating Classification of Chemical Reactions into Classes in Ugi's Reaction Scheme

There are two approaches for classification of chemical reactions: Model-Driven and Data-Driven. In this paper, the authors develop an efficient algorithm based on a model-driven approach developed by Ugi and co-workers for classification of chemical reactions. The authors’ algorithm takes reaction matrix of a chemical reaction as input and generates its appropriate class as output. Reaction matrices being symmetric, matrix implementation of Ugi’s scheme using upper/lower tri-angular matrix is of O(n2) in terms of space complexity. Time complexity of similar matrix implementation is O(n4), both in worst case as well as in average case. The proposed algorithm uses two fixed size look-up tables in a novel way and requires constant space complexity. Time complexity both in worst and average cases of the algorithm is linear. DOI: 10.4018/ijcce.2012070101 2 International Journal of Chemoinformatics and Chemical Engineering, 2(2), 1-14, July-December 2012 Copyright © 2012, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. respectively. Next Ugi’s scheme is discussed under the Classification section. In the fourth section, Methods and Algorithm, we have presented our algorithm based on a novel mapping of Ugi’s scheme into look-up tables for classification of chemical reactions. In the next section we have theoretically obtained space and time complexity results and discussed their implications compared to upper/lower triangular matrix method of implementation of Ugi’s scheme. The last section summarizes our conclusions.