在飞驰的列车上，无法入眠。外面阴雨绵绵，思绪被拉扯到天边。
翻看之前聊天，想起还欠一个读者一篇博客。
于是花了点时间整理一下之前学习 Caffe 时添加自己定义 Layer 及自己定义 ProtoBuffer 參数的简单例程，希望对刚開始学习的人有借鉴意义。
博客内容基于新书《深度学习：21 天实战 Caffe》。书中课后习题答案欢迎读者留言讨论。
以下进入正文。
在使用 Caffe 过程中常常会有这种需求：已有 Layer 不符合我的应用场景；我须要这样这种功能。原版代码没有实现。或者已经实现但效率太低。我有更好的实现。
方案一：简单粗暴的解法——偷天换日
假设你对 ConvolutionLayer 的实现不惬意，那就直接改这两个文件：$CAFFE_ROOT/include/caffe/layers/conv_layer.hpp 和 $CAFFE_ROOT/src/caffe/layers/conv_layer.cpp 或 conv_layer.cu 。将 im2col + gemm 替换为你自己的实现（比方基于 winograd 算法的实现）。
长处：高速迭代，不须要对 Caffe 框架有过多了解，糙快狠准。
缺点：代码难维护，不能 merge 到 caffe master branch，easy给使用代码的人带来困惑（效果和 #define TRUE false 几乎相同）。
方案二：略微温和的解法——千人千面
和方案一相似，仅仅是通过预编译宏来确定使用哪种实现。
比如能够保留 ConvolutionLayer 默认实现，同一时候在代码中添加例如以下段：
#ifdef SWITCH_MY_IMPLEMENTATION // 你的实现代码 #else // 默认代码 #endif
这样能够在须要使用该 Layer 的代码中，添加宏定义：
#define SWITCH_MY_IMPLEMENTATION
就能够使用你的实现。而没有定义该宏的代码，仍然使用原版实现。
长处：能够在新旧实现代码之间灵活切换；
缺点：每次切换须要又一次编译。
方案三：优雅转身——山路十八弯
同一个功能的 Layer 有不同实现。希望能灵活切换又不须要又一次编译代码，该怎样实现？
这时不得不使用 ProtoBuffer 工具了。
首先。要把你的实现，要像正常的 Layer 类一样，分解为声明部分和实现部分。分别放在 .hpp 与 .cpp、.cu 中。Layer 名称要起一个能差别于原版实现的新名称。.hpp 文件置于 $CAFFE_ROOT/include/caffe/layers/，而 .cpp 和 .cu 置于 $CAFFE_ROOT/src/caffe/layers/，这样你在 $CAFFE_ROOT 下运行 make 编译时。会自己主动将这些文件添加构建过程，省去了手动设置编译选项的繁琐流程。
其次，在 $CAFFE_ROOT/src/caffe/proto/caffe.proto 中，添加新 LayerParameter 选项，这样你在编写 train.prototxt 或者 test.prototxt 或者 deploy.prototxt 时就能把新 Layer 的描写叙述写进去，便于改动网络结构和替换其它同样功能的 Layer 了。
最后也是最easy忽视的一点，在 Layer 工厂注冊新 Layer 加工函数，不然在你运行过程中可能会报例如以下错误：
F1002 01:51:22.656038 1954701312 layer_factory.hpp:81] Check failed: registry.count(type) == 1 (0 vs. 1) Unknown layer type: AllPass (known types: AbsVal, Accuracy, ArgMax, BNLL, BatchNorm, BatchReindex, Bias, Concat, ContrastiveLoss, Convolution, Crop, Data, Deconvolution, Dropout, DummyData, ELU, Eltwise, Embed, EuclideanLoss, Exp, Filter, Flatten, HDF5Data, HDF5Output, HingeLoss, Im2col, ImageData, InfogainLoss, InnerProduct, Input, LRN, Log, MVN, MemoryData, MultinomialLogisticLoss, PReLU, Pooling, Power, ReLU, Reduction, Reshape, SPP, Scale, Sigmoid, SigmoidCrossEntropyLoss, Silence, Slice, Softmax, SoftmaxWithLoss, Split, TanH, Threshold, Tile, WindowData)
*** Check failure stack trace: ***
@ 0x10243154e google::LogMessage::Fail()
@ 0x102430c53 google::LogMessage::SendToLog()
@ 0x1024311a9 google::LogMessage::Flush()
@ 0x1024344d7 google::LogMessageFatal::~LogMessageFatal()
@ 0x10243183b google::LogMessageFatal::~LogMessageFatal()
@ 0x102215356 caffe::LayerRegistry<>::CreateLayer()
@ 0x102233ccf caffe::Net<>::Init()
@ 0x102235996 caffe::Net<>::Net()
@ 0x102118d8b time()
@ 0x102119c9a main
@ 0x7fff851285ad start
@ 0x4 (unknown)
Abort trap: 6
以下给出一个实际案例。走一遍方案三的流程。
这里我们实现一个新 Layer，名称为 AllPassLayer。顾名思义就是全通 Layer，“全通”借鉴于信号处理中的全通滤波器，将信号无失真地从输入转到输出。
尽管这个 Layer 并没有什么卵用，可是在这个基础上添加你的处理是很easy的事情。
另外也是出于实验考虑。全通层的 Forward/Backward 函数很easy不须要读者有不论什么高等数学和求导的背景知识。读者使用该层时能够插入到不论什么已有网络中，而不会影响训练、预測的准确性。
首先看头文件：
#ifndef CAFFE_ALL_PASS_LAYER_HPP_
#define CAFFE_ALL_PASS_LAYER_HPP_
#include <vector>
#include "caffe/blob.hpp"
#include "caffe/layer.hpp"
#include "caffe/proto/caffe.pb.h"
#include "caffe/layers/neuron_layer.hpp"
namespace caffe {
template <typename Dtype>
class AllPassLayer : public NeuronLayer<Dtype> {
public:
explicit AllPassLayer(const LayerParameter& param)
: NeuronLayer<Dtype>(param) {}
virtual inline const char* type() const { return "AllPass"; }
protected:
virtual void Forward_cpu(const vector<Blob<Dtype>*>& bottom,
const vector<Blob<Dtype>*>& top);
virtual void Forward_gpu(const vector<Blob<Dtype>*>& bottom,
const vector<Blob<Dtype>*>& top);
virtual void Backward_cpu(const vector<Blob<Dtype>*>& top,
const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom);
virtual void Backward_gpu(const vector<Blob<Dtype>*>& top,
const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom);
};
} // namespace caffe
#endif // CAFFE_ALL_PASS_LAYER_HPP_
再看源文件：
#include <algorithm>
#include <vector>
#include "caffe/layers/all_pass_layer.hpp"
#include <iostream>
using namespace std;
#define DEBUG_AP(str) cout<<str<<endl
namespace caffe {
template <typename Dtype>
void AllPassLayer<Dtype>::Forward_cpu(const vector<Blob<Dtype>*>& bottom,
const vector<Blob<Dtype>*>& top) {
const Dtype* bottom_data = bottom[0]->cpu_data();
Dtype* top_data = top[0]->mutable_cpu_data();
const int count = bottom[0]->count();
for (int i = 0; i < count; ++i) {
top_data[i] = bottom_data[i];
}
DEBUG_AP("Here is All Pass Layer, forwarding.");
DEBUG_AP(this->layer_param_.all_pass_param().key());
}
template <typename Dtype>
void AllPassLayer<Dtype>::Backward_cpu(const vector<Blob<Dtype>*>& top,
const vector<bool>& propagate_down,
const vector<Blob<Dtype>*>& bottom) {
if (propagate_down[0]) {
const Dtype* bottom_data = bottom[0]->cpu_data();
const Dtype* top_diff = top[0]->cpu_diff();
Dtype* bottom_diff = bottom[0]->mutable_cpu_diff();
const int count = bottom[0]->count();
for (int i = 0; i < count; ++i) {
bottom_diff[i] = top_diff[i];
}
}
DEBUG_AP("Here is All Pass Layer, backwarding.");
DEBUG_AP(this->layer_param_.all_pass_param().key());
}
#ifdef CPU_ONLY
STUB_GPU(AllPassLayer);
#endif
INSTANTIATE_CLASS(AllPassLayer);
REGISTER_LAYER_CLASS(AllPass);
} // namespace caffe
时间考虑，我没有实现 GPU 模式的 forward、backward。故本文例程仅支持 CPU_ONLY 模式。
编辑 caffe.proto。找到 LayerParameter 描写叙述，添加一项：
message LayerParameter {
optional string name = 1; // the layer name
optional string type = 2; // the layer type
repeated string bottom = 3; // the name of each bottom blob
repeated string top = 4; // the name of each top blob
// The train / test phase for computation.
optional Phase phase = 10;
// The amount of weight to assign each top blob in the objective.
// Each layer assigns a default value, usually of either 0 or 1,
// to each top blob.
repeated float loss_weight = 5;
// Specifies training parameters (multipliers on global learning constants,
// and the name and other settings used for weight sharing).
repeated ParamSpec param = 6;
// The blobs containing the numeric parameters of the layer.
repeated BlobProto blobs = 7;
// Specifies on which bottoms the backpropagation should be skipped.
// The size must be either 0 or equal to the number of bottoms.
repeated bool propagate_down = 11;
// Rules controlling whether and when a layer is included in the network,
// based on the current NetState. You may specify a non-zero number of rules
// to include OR exclude, but not both. If no include or exclude rules are
// specified, the layer is always included. If the current NetState meets
// ANY (i.e., one or more) of the specified rules, the layer is
// included/excluded.
repeated NetStateRule include = 8;
repeated NetStateRule exclude = 9;
// Parameters for data pre-processing.
optional TransformationParameter transform_param = 100;
// Parameters shared by loss layers.
optional LossParameter loss_param = 101;
// Layer type-specific parameters.
//
// Note: certain layers may have more than one computational engine
// for their implementation. These layers include an Engine type and
// engine parameter for selecting the implementation.
// The default for the engine is set by the ENGINE switch at compile-time.
optional AccuracyParameter accuracy_param = 102;
optional ArgMaxParameter argmax_param = 103;
optional BatchNormParameter batch_norm_param = 139;
optional BiasParameter bias_param = 141;
optional ConcatParameter concat_param = 104;
optional ContrastiveLossParameter contrastive_loss_param = 105;
optional ConvolutionParameter convolution_param = 106;
optional CropParameter crop_param = 144;
optional DataParameter data_param = 107;
optional DropoutParameter dropout_param = 108;
optional DummyDataParameter dummy_data_param = 109;
optional EltwiseParameter eltwise_param = 110;
optional ELUParameter elu_param = 140;
optional EmbedParameter embed_param = 137;
optional ExpParameter exp_param = 111;
optional FlattenParameter flatten_param = 135;
optional HDF5DataParameter hdf5_data_param = 112;
optional HDF5OutputParameter hdf5_output_param = 113;
optional HingeLossParameter hinge_loss_param = 114;
optional ImageDataParameter image_data_param = 115;
optional InfogainLossParameter infogain_loss_param = 116;
optional InnerProductParameter inner_product_param = 117;
optional InputParameter input_param = 143;
optional LogParameter log_param = 134;
optional LRNParameter lrn_param = 118;
optional MemoryDataParameter memory_data_param = 119;
optional MVNParameter mvn_param = 120;
optional PoolingParameter pooling_param = 121;
optional PowerParameter power_param = 122;
optional PReLUParameter prelu_param = 131;
optional PythonParameter python_param = 130;
optional ReductionParameter reduction_param = 136;
optional ReLUParameter relu_param = 123;
optional ReshapeParameter reshape_param = 133;
optional ScaleParameter scale_param = 142;
optional SigmoidParameter sigmoid_param = 124;
optional SoftmaxParameter softmax_param = 125;
optional SPPParameter spp_param = 132;
optional SliceParameter slice_param = 126;
optional TanHParameter tanh_param = 127;
optional ThresholdParameter threshold_param = 128;
optional TileParameter tile_param = 138;
optional WindowDataParameter window_data_param = 129;
optional AllPassParameter all_pass_param = 155;
}
注意新增数字不要和曾经的 Layer 数字反复。
仍然在 caffe.proto 中，添加 AllPassParameter 声明，位置随意。我设定了一个參数，能够用于从 prototxt 中读取预设值。
message AllPassParameter {
optional float key = 1 [default = 0];
}
在 cpp 代码中，通过
this->layer_param_.all_pass_param().key()这句来读取 prototxt 预设值。
在 $CAFFE_ROOT 下运行 make clean，然后又一次 make all。要想一次编译成功，务必规范代码，对常见错误保持敏锐的嗅觉并加以避免。
万事具备，仅仅欠 prototxt 了。
不难，我们写个最简单的 deploy.prototxt，不须要 data layer 和 softmax layer。just for fun。
name: "AllPassTest"
layer {
name: "data"
type: "Input"
top: "data"
input_param { shape: { dim: 10 dim: 3 dim: 227 dim: 227 } }
}
layer {
name: "ap"
type: "AllPass"
bottom: "data"
top: "conv1"
all_pass_param {
key: 12.88
}
}
注意，这里的 type ：后面写的内容，应该是你在 .hpp 中声明的新类 class name 去掉 Layer 后的名称。
上面设定了 key 这个參数的预设值为 12.88。嗯。你想到了刘翔对不正确。
为了检验该 Layer 能否正常创建和运行 forward, backward，我们运行 caffe time 命令并指定刚刚实现的 prototxt ：
$ ./build/tools/caffe.bin time -model deploy.prototxt
I1002 02:03:41.667682 1954701312 caffe.cpp:312] Use CPU.
I1002 02:03:41.671360 1954701312 net.cpp:49] Initializing net from parameters:
name: "AllPassTest"
state {
phase: TRAIN
}
layer {
name: "data"
type: "Input"
top: "data"
input_param {
shape {
dim: 10
dim: 3
dim: 227
dim: 227
}
}
}
layer {
name: "ap"
type: "AllPass"
bottom: "data"
top: "conv1"
all_pass_param {
key: 12.88
}
}
I1002 02:03:41.671463 1954701312 layer_factory.hpp:77] Creating layer data
I1002 02:03:41.671484 1954701312 net.cpp:91] Creating Layer data
I1002 02:03:41.671499 1954701312 net.cpp:399] data -> data
I1002 02:03:41.671555 1954701312 net.cpp:141] Setting up data
I1002 02:03:41.671566 1954701312 net.cpp:148] Top shape: 10 3 227 227 (1545870)
I1002 02:03:41.671592 1954701312 net.cpp:156] Memory required for data: 6183480
I1002 02:03:41.671605 1954701312 layer_factory.hpp:77] Creating layer ap
I1002 02:03:41.671620 1954701312 net.cpp:91] Creating Layer ap
I1002 02:03:41.671630 1954701312 net.cpp:425] ap <- data
I1002 02:03:41.671644 1954701312 net.cpp:399] ap -> conv1
I1002 02:03:41.671663 1954701312 net.cpp:141] Setting up ap
I1002 02:03:41.671674 1954701312 net.cpp:148] Top shape: 10 3 227 227 (1545870)
I1002 02:03:41.671685 1954701312 net.cpp:156] Memory required for data: 12366960
I1002 02:03:41.671695 1954701312 net.cpp:219] ap does not need backward computation.
I1002 02:03:41.671705 1954701312 net.cpp:219] data does not need backward computation.
I1002 02:03:41.671710 1954701312 net.cpp:261] This network produces output conv1
I1002 02:03:41.671720 1954701312 net.cpp:274] Network initialization done.
I1002 02:03:41.671746 1954701312 caffe.cpp:320] Performing Forward
Here is All Pass Layer, forwarding.
12.88
I1002 02:03:41.679689 1954701312 caffe.cpp:325] Initial loss: 0
I1002 02:03:41.679714 1954701312 caffe.cpp:326] Performing Backward
I1002 02:03:41.679738 1954701312 caffe.cpp:334] *** Benchmark begins ***
I1002 02:03:41.679746 1954701312 caffe.cpp:335] Testing for 50 iterations.
Here is All Pass Layer, forwarding.
12.88
Here is All Pass Layer, backwarding.
12.88
I1002 02:03:41.681139 1954701312 caffe.cpp:363] Iteration: 1 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.682394 1954701312 caffe.cpp:363] Iteration: 2 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.683653 1954701312 caffe.cpp:363] Iteration: 3 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.685096 1954701312 caffe.cpp:363] Iteration: 4 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.686326 1954701312 caffe.cpp:363] Iteration: 5 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.687713 1954701312 caffe.cpp:363] Iteration: 6 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.689038 1954701312 caffe.cpp:363] Iteration: 7 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.690251 1954701312 caffe.cpp:363] Iteration: 8 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.691548 1954701312 caffe.cpp:363] Iteration: 9 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.692805 1954701312 caffe.cpp:363] Iteration: 10 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.694056 1954701312 caffe.cpp:363] Iteration: 11 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.695264 1954701312 caffe.cpp:363] Iteration: 12 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.696761 1954701312 caffe.cpp:363] Iteration: 13 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.698225 1954701312 caffe.cpp:363] Iteration: 14 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.699653 1954701312 caffe.cpp:363] Iteration: 15 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.700945 1954701312 caffe.cpp:363] Iteration: 16 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.702761 1954701312 caffe.cpp:363] Iteration: 17 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.704056 1954701312 caffe.cpp:363] Iteration: 18 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.706471 1954701312 caffe.cpp:363] Iteration: 19 forward-backward time: 2 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.708784 1954701312 caffe.cpp:363] Iteration: 20 forward-backward time: 2 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.710043 1954701312 caffe.cpp:363] Iteration: 21 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.711272 1954701312 caffe.cpp:363] Iteration: 22 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.712528 1954701312 caffe.cpp:363] Iteration: 23 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.713964 1954701312 caffe.cpp:363] Iteration: 24 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.715248 1954701312 caffe.cpp:363] Iteration: 25 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.716487 1954701312 caffe.cpp:363] Iteration: 26 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.717725 1954701312 caffe.cpp:363] Iteration: 27 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.718962 1954701312 caffe.cpp:363] Iteration: 28 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.720289 1954701312 caffe.cpp:363] Iteration: 29 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.721837 1954701312 caffe.cpp:363] Iteration: 30 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.723042 1954701312 caffe.cpp:363] Iteration: 31 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.724261 1954701312 caffe.cpp:363] Iteration: 32 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.725587 1954701312 caffe.cpp:363] Iteration: 33 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.726771 1954701312 caffe.cpp:363] Iteration: 34 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.728013 1954701312 caffe.cpp:363] Iteration: 35 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.729249 1954701312 caffe.cpp:363] Iteration: 36 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.730716 1954701312 caffe.cpp:363] Iteration: 37 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.732275 1954701312 caffe.cpp:363] Iteration: 38 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.733809 1954701312 caffe.cpp:363] Iteration: 39 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.735049 1954701312 caffe.cpp:363] Iteration: 40 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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I1002 02:03:41.737144 1954701312 caffe.cpp:363] Iteration: 41 forward-backward time: 2 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.739090 1954701312 caffe.cpp:363] Iteration: 42 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.741575 1954701312 caffe.cpp:363] Iteration: 43 forward-backward time: 2 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.743450 1954701312 caffe.cpp:363] Iteration: 44 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.744732 1954701312 caffe.cpp:363] Iteration: 45 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.745970 1954701312 caffe.cpp:363] Iteration: 46 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.747185 1954701312 caffe.cpp:363] Iteration: 47 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.748430 1954701312 caffe.cpp:363] Iteration: 48 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.749826 1954701312 caffe.cpp:363] Iteration: 49 forward-backward time: 1 ms.
Here is All Pass Layer, forwarding.
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Here is All Pass Layer, backwarding.
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I1002 02:03:41.751124 1954701312 caffe.cpp:363] Iteration: 50 forward-backward time: 1 ms.
I1002 02:03:41.751147 1954701312 caffe.cpp:366] Average time per layer:
I1002 02:03:41.751157 1954701312 caffe.cpp:369] data forward: 0.00108 ms.
I1002 02:03:41.751183 1954701312 caffe.cpp:372] data backward: 0.001 ms.
I1002 02:03:41.751194 1954701312 caffe.cpp:369] ap forward: 1.37884 ms.
I1002 02:03:41.751205 1954701312 caffe.cpp:372] ap backward: 0.01156 ms.
I1002 02:03:41.751220 1954701312 caffe.cpp:377] Average Forward pass: 1.38646 ms.
I1002 02:03:41.751231 1954701312 caffe.cpp:379] Average Backward pass: 0.0144 ms.
I1002 02:03:41.751240 1954701312 caffe.cpp:381] Average Forward-Backward: 1.42 ms.
I1002 02:03:41.751250 1954701312 caffe.cpp:383] Total Time: 71 ms.
I1002 02:03:41.751260 1954701312 caffe.cpp:384] *** Benchmark ends ***
可见该 Layer 能够正常创建、载入预设參数、运行 forward、backward 函数。
实际上对于算法 Layer。还要写 Test Case 保证功能正确。因为我们选择了极为简单的全通 Layer，故这一步能够省去。我这里偷点懒，您省点阅读时间。
感谢各位读者提出的宝贵建议和意见，这些都是无价的有监督学习数据集，是激励我不断 update 的 back prop 源动力。
祝各位同学国庆快乐！