Return a zero matrix

[ChaosPredictor]

I follow the installation process as it's defined in the README, without apex it doesn't work.
apex installed in the following way:

pip uninstall apex
rm -rf apex

git clone https://github.com/ptrblck/apex.git
cd apex
git checkout apex_no_distributed
pip install -v --no-cache-dir ./

otherwise apex.parallel not found.

with apex I'm getting the following warnings:

Warning: using Python fallback for SyncBatchNorm, possibly because apex was installed without --cuda_ext. The exception raised when attempting to import the cuda backend was: No module named 'syncbn'

predict.py:169: UserWarning: ./result/000000_10.png is a low contrast image
skimage.io.imsave(savename, (temp * 256).astype('uint16'))

and the result is just a matrix of zeros.
more information here

Working on ubuntu 18.04 with conda, python 3.7.4, torch 1.0.0, cuda 10.2
gcc 7.5

Any suggestions?

[ChaosPredictor]

I still can't understand why, but I found that LGA2 function in DispAgg returns all zeros matrix.

[ChaosPredictor]

maybe the compile logs can be helpful:

running clean
removing 'build/temp.linux-x86_64-3.7' (and everything under it)
running build
running build_ext
building 'GANet' extension
creating build
creating build/temp.linux-x86_64-3.7
creating build/temp.linux-x86_64-3.7/src
gcc -pthread -B /home/master/anaconda3/envs/GANet/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/usr/local/cuda-10.2/include -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/GANet_cuda.cpp -o build/temp.linux-x86_64-3.7/src/GANet_cuda.o -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=GANet -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
/usr/local/cuda-10.2/bin/nvcc -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/usr/local/cuda-10.2/include -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/GANet_kernel.cu -o build/temp.linux-x86_64-3.7/src/GANet_kernel.o -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --compiler-options '-fPIC' -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=GANet -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
creating build/lib.linux-x86_64-3.7
g++ -pthread -shared -B /home/master/anaconda3/envs/GANet/compiler_compat -L/home/master/anaconda3/envs/GANet/lib -Wl,-rpath=/home/master/anaconda3/envs/GANet/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.7/src/GANet_cuda.o build/temp.linux-x86_64-3.7/src/GANet_kernel.o -L/usr/local/cuda-10.2/lib64 -lcudart -o build/lib.linux-x86_64-3.7/GANet.cpython-37m-x86_64-linux-gnu.so
running clean
removing 'build/temp.linux-x86_64-3.7' (and everything under it)
running clean
running build
running build_ext
building 'sync_bn_cpu' extension
creating build
creating build/temp.linux-x86_64-3.7
creating build/temp.linux-x86_64-3.7/src
creating build/temp.linux-x86_64-3.7/src/cpu
gcc -pthread -B /home/master/anaconda3/envs/GANet/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/cpu/operator.cpp -o build/temp.linux-x86_64-3.7/src/cpu/operator.o -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=sync_bn_cpu -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
In file included from src/cpu/operator.h:1:0,
                 from src/cpu/operator.cpp:1:
/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include/torch/torch.h:7:2: warning: #warning "Including torch/torch.h for C++ extensions is deprecated. Please include torch/extension.h" [-Wcpp]
 #warning \
  ^~~~~~~
gcc -pthread -B /home/master/anaconda3/envs/GANet/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/cpu/sync_bn.cpp -o build/temp.linux-x86_64-3.7/src/cpu/sync_bn.o -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=sync_bn_cpu -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
creating build/lib.linux-x86_64-3.7
g++ -pthread -shared -B /home/master/anaconda3/envs/GANet/compiler_compat -L/home/master/anaconda3/envs/GANet/lib -Wl,-rpath=/home/master/anaconda3/envs/GANet/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.7/src/cpu/operator.o build/temp.linux-x86_64-3.7/src/cpu/sync_bn.o -o build/lib.linux-x86_64-3.7/sync_bn_cpu.cpython-37m-x86_64-linux-gnu.so
running build
running build_ext
building 'sync_bn_gpu' extension
creating build/temp.linux-x86_64-3.7/src/gpu
gcc -pthread -B /home/master/anaconda3/envs/GANet/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/usr/local/cuda-10.2/include -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/gpu/operator.cpp -o build/temp.linux-x86_64-3.7/src/gpu/operator.o -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=sync_bn_gpu -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
/usr/local/cuda-10.2/bin/nvcc -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/torch/csrc/api/include -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/TH -I/home/master/anaconda3/envs/GANet/lib/python3.7/site-packages/torch/lib/include/THC -I/usr/local/cuda-10.2/include -I/home/master/anaconda3/envs/GANet/include/python3.7m -c src/gpu/sync_bn_cuda.cu -o build/temp.linux-x86_64-3.7/src/gpu/sync_bn_cuda.o -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --compiler-options '-fPIC' -DTORCH_API_INCLUDE_EXTENSION_H -DTORCH_EXTENSION_NAME=sync_bn_gpu -D_GLIBCXX_USE_CXX11_ABI=0 -std=c++11
g++ -pthread -shared -B /home/master/anaconda3/envs/GANet/compiler_compat -L/home/master/anaconda3/envs/GANet/lib -Wl,-rpath=/home/master/anaconda3/envs/GANet/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.7/src/gpu/operator.o build/temp.linux-x86_64-3.7/src/gpu/sync_bn_cuda.o -L/usr/local/cuda-10.2/lib64 -lcudart -o build/lib.linux-x86_64-3.7/sync_bn_gpu.cpython-37m-x86_64-linux-gnu.so