symmetric model with fertility sel

C code, parameter file, and Mathematica file for the symmetric model with fertility selection. The positions of entries in the parameter file can be found in the "getinfo" function in the C file.适用于带有生育选择的对称模型的C语言代码、参数文件以及Mathematica文件。参数文件中各条目的位置可在该C文件的"getinfo"函数中查询得到。