The Development of Charge Analysis system by an integration of GA and MEM.

遗传算法（GA）用于搜索和优化基因型中的许多参数，如寻找函数在某个域空间上的最大值。遗传算法的灵感来自于约翰·霍兰德的适应理论。在遗传算法优化中，模式定理提供了适合于自适应的概率解，而在X射线结构分析中，概率解基本上没有用处。在本研究中，我们必须确定一个最优解，而不是概率解。因此，概率解必须进展到最优解。最大熵方法（MEM）是一种非常先进的方法，它具有从概率到最优解进化的能力，这是一个非常困难的过程。在本研究中，发现差分MEM（DMEM）具有很强的分析能力，适用于各种分析过程。两个主要过程描述如下。一种是基于全结构模型的DMEM电荷密度。另一种是基于结构模型的DMEM电荷密度，其中故意省略了一些原子。在这两种情况下，对于本发明的目的，DMEM电荷密度比普通MEM电荷密度有用得多。原因很清楚。DMEM培养液能很容易地显示出微弱的电荷密度。本研究的主要成果是将DMEM与GA相结合。它为大分子材料（如药物化合物）的精确结构分析提供了可能性。

Genetic algorithm (GA) is used in search and optimization of many parameters in genotype, such as finding the maximum of a function over some domain space. GA is inspired by John Holland's theory for adaptation. In GA optimization, the schema theorems provide probabilistic solutions, which is appropriate for adaptation.In an X-ray structural analysis, probabilistic solutions have basically no usefulness. We have to determine an optimum solution in the present study rather than probabilistic solutions. Thus, probabilistic solutions must progress to the optimum solution. At first, we expected that the Maximum Entropy Method (MEM) show abilities in the evolution from probabilistic to optimum solution, which is very difficult process. In the present research, it is found that difference-MEM (DMEM) has great abilities for such process.The DMEM is useful for various situations of analysis process. The two main processes are described as follows. One is the DMEM charge density based on full structure model. The other is the DMEM charge density based on a structure model, in which a few atoms are intentionally omitted. In both cases, the DMEM charge density is much more useful than the ordinary MEM charge density for the present purposes. The reason is very clear. The DMEM can easily reveal the weak charge density. The utilization of DMEM with the combination of GA would be the main achievement of present study. It provides the possibilities for precise structural analysis of the larger molecular materials, such as pharmaceutical compounds.