Tensor_unfold

代码说明：

  张量的模式展开是一个基本的技术，已有各种代码展开结果不尽相同，本代码是根据张量研究领域权威文献“Tensor Deco们positions and Applications”中的公式编写，并经过多次实例验证，与理论描述相符。文件包括两个m文件，一个是按模n展开，而另一个是逆变换，即按模n叠合。(unfolding of the tensor mode is a basic technology, there are a variety of code to make different result. However this code is written by referring to the authority of the tensor field of research literature Tensor Deco their positions and Applications and after several instances verification, is consistent with the theoretical description. The documents include two m-files, one is unfold.m, and the other is the inverse transformation, that is refold.m.)