TAMNUN has four graphic nodes gn001, gn002, gn003 and gn004

These two links connect  to 
a sample shell script 
and to a sample  c file 
as well as a sample queue submit file  run.sh.
to help new users prepare their own codes.
You can downlaod all three ar graph.tar
To work with these
you should enter your home directory and write:

mkdir demo
cd demo
mkdir HelloCL
cd HelloCL 

and place the three files there,
and run compile.sh
and then qsub run.sh

The queue to access the graphic nodes is:
workq at the moment, a separate queue will be announced shortly - after 
this isannounced run.sh will need adaptation.

The code and scripts were prepared by Dr Igal Raisin.

The source of compile.sh is:

g++ hellocl.c -o hellocl -I/usr/local/cuda/include -lOpenCL

The source of hellocl.c is:

/* Simple Hello World for OpenCL, written in C.
 * For real code, check for errors. The error code is stored in all calls here,
 * but no checking is done, which is certainly bad. It'll likely simply crash
 * right after a failing call.
 * On GNU/Linux with nVidia OpenCL, program builds with -lOpenCL.
 * Not sure about other platforms.



const char rot13_cl[] = "				\
__kernel void rot13					\
    (   __global    const   char*    in			\
    ,   __global            char*    out		\
    )							\
{							\
    const uint index = get_global_id(0);		\
    char c=in[index];					\
    if (c<'A' || c>'z' || (c>'Z' && c<'a')) {		\
        out[index] = in[index];				\
    } else {						\
        if (c>'m' || (c>'M' && c<'a')) {		\
	    out[index] = in[index]-13;			\
	} else {					\
	    out[index] = in[index]+13;			\
	}						\
    }							\
}							\

void rot13 (char *buf)
    int index=0;
    char c=buf[index];
    while (c!=0) {
        if (c<'A' || c>'z' || (c>'Z' && c<'a')) {
            buf[index] = buf[index];
        } else {
            if (c>'m' || (c>'M' && c<'a')) {
	        buf[index] = buf[index]-13;
	    } else {
	        buf[index] = buf[index]+13;

int main() {
	char buf[]="Hello, World!";
	size_t srcsize, worksize=strlen(buf);
	cl_int error;
	cl_platform_id platform;
	cl_device_id device;
	cl_uint platforms, devices;

	// Fetch the Platform and Device IDs; we only want one.
	error=clGetPlatformIDs(1, &platform, &platforms);
	error=clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 1, &device, &devices);
	cl_context_properties properties[]={
		CL_CONTEXT_PLATFORM, (cl_context_properties)platform,
	// Note that nVidia's OpenCL requires the platform property
	cl_context context=clCreateContext(properties, 1, &device, NULL, NULL, &error)
	cl_command_queue cq = clCreateCommandQueue(context, device, 0, &error);
	rot13(buf);	// scramble using the CPU
	puts(buf);	// Just to demonstrate the plaintext is destroyed

	//char src[8192];
	//FILE *fil=fopen("rot13.cl","r");
	//srcsize=fread(src, sizeof src, 1, fil);
	const char *src=rot13_cl;

	const char *srcptr[]={src};
	// Submit the source code of the rot13 kernel to OpenCL
	cl_program prog=clCreateProgramWithSource(context,
		1, srcptr, &srcsize, &error);
	// and compile it (after this we could extract the compiled version)
	error=clBuildProgram(prog, 0, NULL, "", NULL, NULL);

	// Allocate memory for the kernel to work with
	cl_mem mem1, mem2;
	mem1=clCreateBuffer(context, CL_MEM_READ_ONLY, worksize, NULL, &error);
	mem2=clCreateBuffer(context, CL_MEM_WRITE_ONLY, worksize, NULL, &error);
	// get a handle and map parameters for the kernel
	cl_kernel k_rot13=clCreateKernel(prog, "rot13", &error);
	clSetKernelArg(k_rot13, 0, sizeof(mem1), &mem1);
	clSetKernelArg(k_rot13, 1, sizeof(mem2), &mem2);

	// Target buffer just so we show we got the data from OpenCL
	char buf2[sizeof buf];

	// Send input data to OpenCL (async, don't alter the buffer!)
	error=clEnqueueWriteBuffer(cq, mem1, CL_FALSE, 0, worksize, buf, 0, NULL, NULL
	// Perform the operation
	error=clEnqueueNDRangeKernel(cq, k_rot13, 1, NULL, &worksize, &worksize, 0, NULL, NULL);
	// Read the result back into buf2
	error=clEnqueueReadBuffer(cq, mem2, CL_FALSE, 0, worksize, buf2, 0, NULL, NULL
	// Await completion of all the above
	// Finally, output out happy message.