How to use torch in C++ code

[Wuxia Zhao]

For example, the testTorch.lua is as followings:

require 'torch'

function test(img)

  -- img is torch.FloatTensor(3,256,256)

  img[1][1][1] = 0

  return img

end

How to call function named test(img) in C++ code?

Could you help me to give an C++ example?

[soumith]

Android C++ example: 

https://github.com/soumith/torch-android/blob/master/android-demo/jni/torchdemo.cpp

General tutorial:

http://csl.name/lua/

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[Wuxia Zhao]

my lua file is :

function testTensor(img)

img[1] = 0.5;

print(img[1])

return img;

end

and my C++ file is:

 

int main()

{

 lua_State* L = luaL_newstate();

 luaL_openlibs(L);

 if (luaL_dofile(L,"func.lua") != 0)

 {

  std::cout<<"Load Lua File Error"<<std::endl;

 }

int numElements = 100;

float *mydata = new float[numElements];

THFloatStorage *mystorage =  THFloatStorage_newWithData(mydata, numElements);

THFloatTensor* mytensor = THFloatTensor_newWithStorage1d(mystorage, 0, numElements, 1);

lua_getglobal(L,"testTensor");    //testTensor

【const char* torch_Tensor_id = luaT_typenameid(L, "torch.Tensor");】——which got SegmentFault when running:

//luaT_newmetatable(L, "torch.Tensor", NULL, NULL, NULL, NULL);——which got SegmentFault when running as well:

luaT_pushudata(L, (void *)mytensor, torch_Tensor_id);

lua_call(L,1,1);

delete[] mydata;

 return 0;

}

 

On http://greendotblade3.cs.nyu.edu/torch/luat/index.html#luat_newmetatable, it says before calling  luaT_pushudata(lua_State *L, void *udata, const char *tname), " tname must be a valid Torch name registered with luaT_newmetatable."

   So I add  luaT_newmetatable, but failed. And then I use luaT_typenameid, filed again.

Could you help me to figure out why? And how to write the code to be accepted?

 

[Wuxia Zhao]

Besides, when I add a line:

require "torch"

in the lua file, luaL_dofile(L,"func.lua") fails.

How to fix it?

My make command is : g++ -I /usr/local/include -o test test.c -llua -lluaT -lTH -lm -ldl -L /usr/local/lib

[Konstantinos Mentzelos]

It's being a long time since you asked the question, but I have the same problem. How did you fix the problem with 'require'?