title
Concat Layer

Concat Layer

Layer type: Concat
Doxygen Documentation
Header: ./include/caffe/layers/concat_layer.hpp
CPU implementation: ./src/caffe/layers/concat_layer.cpp
CUDA GPU implementation: ./src/caffe/layers/concat_layer.cu
Input
- n_i * c_i * h * w for each input blob i from 1 to K.
Output
- if axis = 0: (n_1 + n_2 + ... + n_K) * c_1 * h * w, and all input c_i should be the same.
- if axis = 1: n_1 * (c_1 + c_2 + ... + c_K) * h * w, and all input n_i should be the same.

Sample

layer {
  name: "concat"
  bottom: "in1"
  bottom: "in2"
  top: "out"
  type: "Concat"
  concat_param {
    axis: 1
  }
}

The Concat layer is a utility layer that concatenates its multiple input blobs to one single output blob.

Parameters

Parameters (ConcatParameter concat_param)
- Optional
  - axis [default 1]: 0 for concatenation along num and 1 for channels.
From ./src/caffe/proto/caffe.proto):

{% highlight Protobuf %} {% include proto/ConcatParameter.txt %} {% endhighlight %}