Installation fails on Ubuntu 16.04 (‘memcpy’ was not declared in this scope)

[andreaskoepf]

Just tried to install Torch on a fresh Ubuntu 16.04 machine. Compilation of cutorch failed with the following error message:

/usr/include/string.h: In function 'void* __mempcpy_inline(void*, const void*, size_t)':
/usr/include/string.h:652:42: error: 'memcpy' was not declared in this scope
     return (char *) memcpy (__dest, __src, __n) + __n;

Caffe has a similar issue: BVLC/caffe#4046
Tensorflow had this too: tensorflow/tensorflow#1346

Solution is to define _FORCE_INLINES, e.g. add set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORCE_INLINES") to the CMakeLists.txt files of ctorch, cunn and cunnx.

Could somebody more familiar with the CMake configurations of those projects please check what to do?

[soumith]

@andreaskoepf where'd you get a 16.04 machine? are they available on ec2?

[andreaskoepf]

@soumith I installed on the premises with an iso-image downloaded from ubuntu.com.

[andreaskoepf]

It seems @hughperkins is already working on it torch/cutorch#401 👍

[hughperkins]

Well "worked" on it. I have my own distro fork, which works ok :-) https://github.com/hughperkins/distro (On the other hand, whilst my Ubuntu is cutting edge, but lts, I've decided to create my own Torch lts, so if you use my distro, you get February version of Torch :-D ).

For bleeding edge torch "sid", you'll probalby need to fix it yourself, and submit a PR :-)

[andreaskoepf]

@hughperkins ok. Was this the relevant change? hughperkins/distro-cl@357ed7b Anything else?

[hughperkins]

That's how I changed it. But in hindsight I'm not sure this is the best place to control the definition. It is ok for me, since I force everyone on OpenCL to use my distro, and only my distro :-D ie, not allowed to do luarocks install cutorch.

However, to support luarocks install cutorch, probably the change should be in cutorch's CMakeLists.txt. Something like add_definitions(-D_FORCE_INLINES), or update the CMAKE_CXX_FLAGS, as you/we both did, should work.

(Edit: note that you need to update the rockspec too, if you use my current approach, torch/cutorch#402 , but this is already merged to Torch "sid", so should be ok)

[hughperkins]

Finally, I moved my fix into CMakeLists.txt actually hughperkins/cutorch@f1f62a1 When I say 'moved', I mean, 'added', need to remove the old 'fix'.

[hughperkins]

To be fair, I'm getting:

gcc-4.9: internal compiler error: Killed (program cc1plus)
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-4.9/README.Bugs> for instructions.
CMake Error at THC_generated_THCTensorMath2.cu.o.cmake:266 (message):
  Error generating file
  /home/ubuntu/torch-cl/extra/cutorch/build/lib/THC/CMakeFiles/THC.dir//./THC_generated_THCTensorMath2.cu.o

... so I've been switching to ec2 14.04 to finish building. I assumed it's because my laptop only has 4GB memory, but it might be something more critical....

[hughperkins]

(note: after dropping the -j threads to 1, cutorch built ok on my 16.04 laptop; tests run ok).

[hughperkins]

(but: need to modify cmakelists for cunn too it seems :-D )

[hughperkins]

(so, it would be tempting to add the change to https://github.com/hughperkins/FindCUDA really... if someone can see how to do that, I'll probably accept a PR )

[hughperkins]

(relevant commit for cunn for now hughperkins/cunn@3a752e5 )

[lukeyeager]

@hughperkins FWIW I tried your distro fork and it solved all my build issues. Thanks!

EDIT - now that the CUDA 8.0 RC is available, everyone should start using that on Ubuntu 16.04

[hughperkins]

cool :-)

[notkarol]

A workaround is to install Cuda 8 directly from the 16.04 run file and remove Ubuntu's nvidia-cuda-toolkit package.

[shrx]

@notkarol can you provide a link?

[notkarol]

https://developer.nvidia.com/cuda-release-candidate-download

Log in then navigate: Linux -> x86_64 -> Ubuntu -> 16.04 -> runfile (local) and download cuda_8.0.27_linux-run

[lukeyeager]

I'd recommend you use the deb package instead.