wangxiao@wangxiao-GTX980:~/Downloads/caffe-master$ make -j8
find: `wangxiao/bvlc_alexnet/spl': No such file or directory
find: `caffemodel': No such file or directory
find: `wangxiao/bvlc_alexnet/0.77': No such file or directory
find: `caffemodel': No such file or directory
NVCC src/caffe/layers/euclidean_loss_layer.cu
src/caffe/layers/euclidean_loss_layer.cu(41): error: a value of type "const float *" cannot be used to initialize an entity of type "float *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=float]"
(140): here
src/caffe/layers/euclidean_loss_layer.cu(42): error: a value of type "const float *" cannot be used to initialize an entity of type "float *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=float]"
(140): here
src/caffe/layers/euclidean_loss_layer.cu(41): error: a value of type "const double *" cannot be used to initialize an entity of type "double *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=double]"
(140): here
src/caffe/layers/euclidean_loss_layer.cu(42): error: a value of type "const double *" cannot be used to initialize an entity of type "double *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=double]"
(140): here
4 errors detected in the compilation of "/tmp/tmpxft_000007e5_00000000-16_euclidean_loss_layer.compute_50.cpp1.ii".
make: *** [.build_debug/cuda/src/caffe/layers/euclidean_loss_layer.o] Error 1
wangxiao@wangxiao-GTX980:~/Downloads/caffe-master$
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原因分析：
主要是因为，在欧式距离损失函数中，我增添了以下两句话：
Dtype* diff_cpu_data = bottom[i]->mutable_cpu_diff();
Dtype* label_data = bottom[1]->cpu_data(); // label data: 0 or 1
Dtype* predict_data = bottom[0]->cpu_data(); // predict data
再来看看提示的错误：
src/caffe/layers/euclidean_loss_layer.cu(41): error: a value of type "const float *" cannot be used to initialize an entity of type "float *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=float]"
(140): here
src/caffe/layers/euclidean_loss_layer.cu(42): error: a value of type "const float *" cannot be used to initialize an entity of type "float *"
detected during instantiation of "void caffe::EuclideanLossLayer<Dtype>::Backward_gpu(const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &, const std::vector<__nv_bool, std::allocator<__nv_bool>> &, const std::vector<caffe::Blob<Dtype> *, std::allocator<caffe::Blob<Dtype> *>> &) [with Dtype=float]"
(140): here
肯定是少了 const 约束：
so , 改为：
const Dtype* label_data = bottom[1]->cpu_data(); // label data: 0 or 1
const Dtype* predict_data = bottom[0]->cpu_data(); // predict data
在编译，就ok啦 ～～
2. 问题2：
CXX src/caffe/layers/accuracy_layer.cpp
src/caffe/layers/accuracy_layer.cpp: In instantiation of ‘void caffe::AccuracyLayer<Dtype>::Forward_cpu(const std::vector<caffe::Blob<Dtype>*>&, const std::vector<caffe::Blob<Dtype>*>&) [with Dtype = float]’:
src/caffe/layers/accuracy_layer.cpp:286:1: required from here
src/caffe/layers/accuracy_layer.cpp:98:21: error: assignment of read-only location ‘*(bottom_data + 84u)’
bottom_data[21] = 1; bottom_data[22] = 0; bottom_data[23] = 0; bottom_data[24] = 0;
看到错误就应该知道：错误的原因是给只读的变量赋值了。。。
但是，又想改变那个值，来作为最后求解的结果，怎么办呢？ 好吧，那就只好先将该变量存到一个中间变量里面去了，但是，问题又来了，原本const 的变量可以赋值给普通的变量么？
例如： float a = const float b ? 这样ok么？我觉得不ok，先试试吧。。。
