NArray is an Numerical N-dimensional Array class. Supported element types are 1/2/4-byte Integer, single/double-precision Real/Complex, and Ruby Object. This extension library incorporates fast calculation and easy manipulation of large numerical arrays into the Ruby language. NArray has features similar to NumPy, but NArray has vector and matrix subclasses.
很棒的东东，特别是你需要处理一些数学矩阵运算的时候。它可以允许你创建任何维数的矩阵，并且提供了必要的数学运算支持。有一些demo可以学习，不难掌握。
check this out: http://narray.rubyforge.org/