SIMULATED ANNEALING CONSTRUCTION OF MOLECULAR GRAPHS WITH REQUIRED PROPERTIES

The method of simulated annealing for the construction of molecular gr aphs with required properties was studied. The method depends on the a lready available functional relationship that transforms molecular str uctural features into a numerical value of a property. The simulated a nnealing was initialized by a randomly generated molecular graph. A mo lecular graph was perturbed onto another molecular graph so that start ing from a randomly selected point the rest of the numerical code of t he current graph was replaced by a randomly generated code. The accept ance of the generated code to the next process of simulated annealing was solved by the Metropolis criterion. After the prescribed number of steps the temperature was multiplicatively decreased. Two types of mo lecular graphs were studied. The first type of molecular graphs was ac yclic graphs (trees) that are simply represented by a numerical code c omposed of the same number of entries as the number of vertices in mol ecular graphs. perturbation operations consist of simple changes of nu merical codes. The second type of molecular graphs was cyclic connecte d graphs (q > p - 1, where p and q are numbers of vertices and edges, respectively) that are represented by the lower-triangle part of adjac ency matrices. The efficiency of the proposed method is illustrated by model calculations, wherein molecular graphs with required properties are constructed.