Caffe installation in ubuntu 14.04

Question

I'm following https://github.com/BVLC/caffe/wiki/Ubuntu-14.04-ec2-instance link for installing caffe on my machine. But when i write command $ make all i get these errors

/usr/local/cuda/bin/nvcc -ccbin=g++ -Xcompiler -fPIC -DNDEBUG -O2 -I/usr/local/include/python2.7 -I/usr/local/lib/python2.7/dist-packages/numpy/core/include -I/usr/local/include -Ibuild/src -I./src -I./include -I/usr/local/cuda/include -gencode arch=compute_20,code=sm_20 -gencode arch=compute_20,code=sm_21 -gencode arch=compute_30,code=sm_30 -gencode arch=compute_35,code=sm_35 -c src/caffe/util/math_functions.cu -o build/src/caffe/util/math_functions.cuo

Error 1:
src/caffe/util/math_functions.cu(140): error: calling a __host__ function("std::signbit<float> ") from a __global__ function("caffe::sgnbit_kernel<float> ") is not allowed

Error 2:
src/caffe/util/math_functions.cu(140): error: calling a __host__ function("std::signbit<double> ") from a __global__ function("caffe::sgnbit_kernel<double> ") is not allowed

2 errors detected in the compilation of "/tmp/tmpxft_00003368_00000000-12_math_functions.compute_35.cpp1.ii".
make: *** [build/src/caffe/util/math_functions.cuo] Error 2

I'm new to this and can't really figure out what package is missing

Answer 1

(This worked for an unmerged longjon caffe branch.)

In caffe/include/caffe/util/math_functions.hpp

try changing

using std::signbit;
DEFINE_CAFFE_CPU_UNARY_FUNC(sgnbit, y[i] = signbit(x[i])); 

to

// using std::signbit;
DEFINE_CAFFE_CPU_UNARY_FUNC(sgnbit, y[i] = std::signbit(x[i]));