Study On Several Problems In Developing Of Statistics Software

In the development of ForStat, several problems are chosen and studied. They are:1 design and implementation of nonlinear least Square Algorithm,2 design of general formula expositor,3 design and implementation of software encryption scheme and4 making of help files system. The conclusion is as follows:Based on Newton Algorithm and its structural analysis, using symbol calculation to get derivative, complied expression to get numerical value and passing parameters in the forms of vector, Hessen matrix is calculated. Local convergence of Newton algorithm is solved by means of trust region method. The numeric test shows the Algorithm has more precision, better global convergence and stability than SPSS. The Algorithm is not only suit to small residual problem, but also could solve the problem with high nonlinear-grade. As for linear regression, the algorithm could obtain accurate result through one iterative, therefore, linear problem is the same as nonlinear problem. With properly transformed, the algorithm could solve nonlinear equations.Scanning each character in the expression to separate and record operators, operational symbols and data types of operators, when expression being correct in syntax, recording interpreter executive order based on precedence of operator, a general expression interpreter is designed. The interpreter not only is used for numerical value and string computation, but also is easy to extend its functions, and when batch converting data, it could catch run error and continue to successive data. The numeric test shows that the interpreter is slower than programming language in the speed, but basically satisfies ForStat system request, and the fact that the extended function speed is little slower than MATLAB.Taking a floppy disk with physical bad sector as key disk, when initialization, user legal statue is confirmed by locating bad sectors. Based on computer hardware information, the machine dactylogram is obtained through encryption algorithm. Considering software system and configure, encryption project aimed to protect software has been designed and implemented. According to warrant, the application could be setup in one or many computers, when reaching warranted number, taking key disk as softdog, the application could run in different computers. In the process of setup, the interface with user is not necessary so as to protect developer copyright andkeep user hardware information from leaking.Online help files are important part of the application. Organizing different topics of help files in the form of system menu function, using such special software as FrontPage, to design different topics, structuring the help files project with Windows help software, the online help is embedded in the application. It not only could find the topic relative to specified function, but also rapidly locate all user interested topic by content, index and find, is easy to jump in between different topics by hyperlink.