Armadillo_ C++ linear algebra library

代码说明：

  Armadillo C++ Library 是一种C++的线性代数库（矩阵数学）以取得良好的平衡速度与易用性。整数，浮点，而复杂的数字支持，以及一个子集，三角和统计功能。各种矩阵分解是通过可选的集成 与LAPACK和Atlas 库(Armadillo C++ Library is a linear algebra Library of C++ (matrix mathematics) to achieve good balance speed and ease of use. Integer, floating-point, and complex digital support, as well as a subset of trigonometric and statistical functions. Various matrix decompositions are made through optional integration with the LAPACK and Atlas Libraries)