How to fix error : unrecognized token in Cuda code with nvcc compiler

I wrote this simple code Cuda in Notepad, which I followed in example: http://www.mathworks.com/help/distcomp/executing-cuda-or-ptx-code-on-the-gpu.html

_global_ void add1( double * pi, double c ) { *pi += c; }

>>then I run it on command line in the current directory: nvcc test.cu I received error with a lot of line "error : unrecognized token"

I don't know what is it and how to fix it. Please help me! I use Cuda 5.0, GPU 720M with Cuda-capable 2.0 Thanks!

Answer 1

[Ben Tordoff]

There are two problems with what you have attempted, one just a typo and the solution to the other will depend on what you are trying to do. First the typo: you are missing an underscore from each side of the global decorator - they should be double underscores:

__global__ void add1(double * pi, double c) 
{ 
  *pi += c; 
}

Now the more important question: what are you trying to achieve? If you are trying to create a PTX file for use with parallel.gpu.CUDAKernel then you need to compile to PTX:

$ nvcc -ptx -arch=sm_20 <filename>.cu

which will procude <filename>.ptx. If you are trying to make a standalone executable then you need to also define a main function as you would for any C++ program.

[HongTu Nguyen]

Thanks for your answer!

But...I corrected it, it's still that error? I don't know what the reason? :(

I just want to compile this file to use in Matlab.

I use Cuda version 5.0, GPU Geforce 720M with Matlab R2012b

[Ben Tordoff]

Can you post what the code now looks like, the new command you used to compile it and what the error was?

[HongTu Nguyen]

Here is my code (I wrote it following the instruction of website: http://www.mathworks.com/help/distcomp/executing-cuda-or-ptx-code-on-the-gpu.html)

__global__ void add1( double * pi, double c ) 

 {
    *pi += c;
 }

I saved it in notepad named: test.cu Then I compiled it in command line, with command:

>>nvcc -ptx test.cu

or I try to use your command:

>>nvcc -ptx -arch=sm_20 test.cu

It has the same error, and the error shows the same picture I've posted.

I do what's wrong? Please help me.

Thanks!

[HongTu Nguyen]

Oh...I'm sorry...I'm so silly...

I've created the new notepad file and wrote it again myself.

And it's ok!

I think the old file I copy from website, so it had something wrong :(

Many thanks for your help!

Then...I have question:

**The command: nvcc -ptx -arch=sm_20 < filename.cu>

What "-arch=sm_20" mean?

**And when I compile by command: nvcc -ptx < filenam.cu> (not -arch=sm_20), it still creates test.ptx file.

>>so what is difference?

**And then, when I compile by command: nvcc < filenam.cu>, it has error look like: