todo

该文件为c++的数学函数库!是一个非常有用的编程工具.它含有各种数学函数,为科学计算、工程应用等程序编写提供方便！

* Reorganize siman interfaces to allow iterative use.

* Maybe the routines can be made to work with pointers instead of structs
  so that only pointer manipulation is done by the siman algorithm and
  there is no need for malloc. A call would look something like 
  siman(&start,&result, ...)