A practical simulated annealing program and its application to quantitative CBED pattern matching

Abstract

A modified simulated annealing (SA) program is presented (source code available from the authors). The program was used for the refinement procedure in quantitative convergent beam diffraction (QCBED). Considering the practical situation in QCBED, three modifications have been made to the conventional SA algorithm. First, a most probable search boundary (MPB) was suggested, which guarantees the program to search mainly within the MPB, but allows it also to go out of the boundary sometimes. Secondly, the MPB was set to shrink during the minimization. This algorithm decreases the computing time significantly. Thirdly, a more meaningful stop criterion was adopted using the nominal physical precision of each refinement parameter. The feasibility and the efficiency of the modified program were tested using both calculated and experimental CBED patterns. The presented program is proved to be capable of high performance.