NSC++: Non-standard cosmologies in C++

We introduce NSC++, a header-only C++ library that simulates the evolution of the plasma and a decaying fluid in the early Universe. NSC++ can be used in C++ programs or called directly from python scripts without significant overhead. There is no special installation process or external dependencies. Furthermore, there are example programs that can be modified to handle several cases.本研究介绍了NSC++——一款仅头文件式C++库，可用于模拟早期宇宙中等离子体与衰变流体的演化过程。该库既可以嵌入C++程序中使用，也可直接从Python脚本调用，且不会带来显著的性能开销。其无需特殊安装流程，亦无外部依赖项。此外，该库附带示例程序，用户可对其进行修改以适配多种应用场景。