############Basic Concept############This paper introduces the basic concepts of Paddle:- `Guide to Fluid Programming <./programming_guide/programming_guide_en.html>`_ :introduces the basic concept and usage of Paddle.- `LoD-Tensor User Guide <lod_tensor_en.html>`_ : LoD-Tensor is a high-level feature of Paddle. It adds sequence information on the basis of tensor and supports processing variable length data.