Ubuntu 16.04 - torch installation failure

[shriphani]

Hi,

I am following these instructions: http://torch.ch/docs/getting-started.html and I get this on the final command:

/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;
                                          ^
CMake Error at THC_generated_THCBlas.cu.o.cmake:267 (message):
  Error generating file
  /home/shriphani/torch/extra/cutorch/build/lib/THC/CMakeFiles/THC.dir//./THC_generated_THCBlas.cu.o


lib/THC/CMakeFiles/THC.dir/build.make:70: recipe for target 'lib/THC/CMakeFiles/THC.dir/THC_generated_THCBlas.cu.o' failed
make[2]: *** [lib/THC/CMakeFiles/THC.dir/THC_generated_THCBlas.cu.o] Error 1
make[2]: *** Waiting for unfinished jobs....
/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;
                                          ^

Is there a simple workaround?

Thanks,
S.

[shriphani]

More info, I made an issue on this repo since this is what git remote show origin points to.

[soumith]

hi @shriphani

This is a bug in CUDA 7.5 + gcc > 4.9

This was reported before here: torch/torch7#670

The easiest way to fix it is to upgrade to CUDA 8.0

If you cant, we fixed it via some workaround flags here: https://github.com/torch/cutorch/blob/master/lib/THC/CMakeLists.txt#L13-L20

I am not sure why they are not being considered in your case.
I tested with a 16.04 machine just now, and it seems to compile fine for me.

[FabbyD]

In case people can't upgrade to 8.0, I was able to make it work with the changes proposed in: tensorflow/tensorflow#1066

I'm using Ubuntu 16.04 LTS, gcc 5, Cuda 7.5.

~/torch/extra/cutorch/lib/THC$ git diff CMakeLists.txt
diff --git a/lib/THC/CMakeLists.txt b/lib/THC/CMakeLists.txt
index 31184af..19639bd 100644
--- a/lib/THC/CMakeLists.txt
+++ b/lib/THC/CMakeLists.txt
@@ -17,7 +17,7 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "4.9.3")
     if(CUDA_VERSION VERSION_LESS "8.0")
       MESSAGE(STATUS "Found gcc >=5 and CUDA <= 7.5, adding workaround C++ flags")
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORCE_INLINES")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORCE_INLINES -D_MWAITXINTRIN_H_INCLUDED -D__STRICT_ANSI__")
     endif(CUDA_VERSION VERSION_LESS "8.0")
   endif(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "4.9.3")
 endif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")

Hope it helps other.

[soumith]

@FabbyD thanks for that. i pushed the additional fixes into cutorch and cunn