im2col

• File type: Im2col
• Header: ./include/caffe/layers/im2col_layer.hpp
• CPU implementation: ./src/caffe/layers/im2col_layer.cpp
• CUDA GPU implementation: ./src/caffe/layers/im2col_layer.cu

Im2col is a helper for doing the image-to-column transformation that you most likely do not need to know about. This is used in Caffe's original convolution to do matrix multiplication by laying out all patches into a matrix.