|
|
--- |
|
|
title: Concat Layer |
|
|
--- |
|
|
|
|
|
# Concat Layer |
|
|
|
|
|
* Layer type: `Concat` |
|
|
* [Doxygen Documentation](http://caffe.berkeleyvision.org/doxygen/classcaffe_1_1ConcatLayer.html) |
|
|
* Header: [`./include/caffe/layers/concat_layer.hpp`](https://github.com/BVLC/caffe/blob/master/include/caffe/layers/concat_layer.hpp) |
|
|
* CPU implementation: [`./src/caffe/layers/concat_layer.cpp`](https://github.com/BVLC/caffe/blob/master/src/caffe/layers/concat_layer.cpp) |
|
|
* CUDA GPU implementation: [`./src/caffe/layers/concat_layer.cu`](https://github.com/BVLC/caffe/blob/master/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`](https://github.com/BVLC/caffe/blob/master/src/caffe/proto/caffe.proto)): |
|
|
|
|
|
{% highlight Protobuf %} |
|
|
{% include proto/ConcatParameter.txt %} |
|
|
{% endhighlight %} |
|
|
|
