Xie et al. proposed a variant of ResNet that is codenamed ResNeXt with the following building block: This may look familiar to you as it is very similar to the Inception module of GoogleNet, they both follow the split-transform-merge paradigm, except in this variant, the outputs of different paths are merged by adding them together, while in GoogleNet they are depth-concatenated. Another difference is that in GoogleNet, each path is different (1x1, 3x3 and 5x5 convolution) from each other, while in this architecture, all paths share the same topology.