//+------------------------------------------------------------------+
//| OpenCL kernel |
//+------------------------------------------------------------------+
const string
cl_src=
//--- by default some GPU doesn't support doubles
//--- cl_khr_fp64 directive is used to enable work with doubles
"#pragma OPENCL EXTENSION cl_khr_fp64 : enable \r\n"
//--- OpenCL kernel function
"__kernel void Test_GPU(__global double *data, \r\n"
" const int N, \r\n"
" const int total_arrays) \r\n"
" { \r\n"
" uint kernel_index=get_global_id(0); \r\n"
" if (kernel_index>total_arrays) return; \r\n"
" uint local_start_offset=kernel_index*N; \r\n"
" for(int i=0; i<N; i++) \r\n"
" { \r\n"
" data[i+local_start_offset] *= 2.0; \r\n"
" } \r\n"
" } \r\n";
//+------------------------------------------------------------------+
//| Test_CPU |
//+------------------------------------------------------------------+
bool Test_CPU(double &data[],const int N,const int id,const int total_arrays)
{
//--- check array size
if(ArraySize(data)==0) return(false);
//--- check array index
if(id>total_arrays) return(false);
//--- calculate local offset for array with index id
int local_start_offset=id*N;
//--- multiply elements by 2
for(int i=0; i<N; i++)
{
data[i+local_start_offset]*=2.0;
}
return true;
}
//---
#define ARRAY_SIZE 100 // size of the array
#define TOTAL_ARRAYS 5 // total arrays
//--- OpenCL handles
int cl_ctx; // OpenCL context handle
int cl_prg; // OpenCL program handle
int cl_krn; // OpenCL kernel handle
int cl_mem; // OpenCL buffer handle
//---
double DataArray1[]; // data array for CPU calculation
double DataArray2[]; // data array for GPU calculation
//+------------------------------------------------------------------+
//| Script program start function |
//+------------------------------------------------------------------+
int OnStart()
{
//--- initialize OpenCL objects
//--- create OpenCL context
if((cl_ctx=CLContextCreate())==INVALID_HANDLE)
{
Print("OpenCL not found. Error=",GetLastError());
return(1);
}
//--- create OpenCL program
if((cl_prg=CLProgramCreate(cl_ctx,cl_src))==INVALID_HANDLE)
{
CLContextFree(cl_ctx);
Print("OpenCL program create failed. Error=",GetLastError());
return(1);
}
//--- create OpenCL kernel
if((cl_krn=CLKernelCreate(cl_prg,"Test_GPU"))==INVALID_HANDLE)
{
CLProgramFree(cl_prg);
CLContextFree(cl_ctx);
Print("OpenCL kernel create failed. Error=",GetLastError());
return(1);
}
//--- create OpenCL buffer
if((cl_mem=CLBufferCreate(cl_ctx,ARRAY_SIZE*TOTAL_ARRAYS*sizeof(double),CL_MEM_READ_WRITE))==INVALID_HANDLE)
{
CLKernelFree(cl_krn);
CLProgramFree(cl_prg);
CLContextFree(cl_ctx);
Print("OpenCL buffer create failed. Error=",GetLastError());
return(1);
}
//--- set OpenCL kernel constant parameters
CLSetKernelArgMem(cl_krn,0,cl_mem);
CLSetKernelArg(cl_krn,1,ARRAY_SIZE);
CLSetKernelArg(cl_krn,2,TOTAL_ARRAYS);
//--- prepare data arrays
ArrayResize(DataArray1,ARRAY_SIZE*TOTAL_ARRAYS);
ArrayResize(DataArray2,ARRAY_SIZE*TOTAL_ARRAYS);
//--- fill arrays with data
for(int j=0; j<TOTAL_ARRAYS; j++)
{
//--- calculate local start offset for jth array
uint local_offset=j*ARRAY_SIZE;
//--- prepare array with index j
for(int i=0; i<ARRAY_SIZE; i++)
{
//--- fill arrays with function MathCos(i+j);
DataArray1[i+local_offset]=MathCos(i+j);
DataArray2[i+local_offset]=MathCos(i+j);
}
};
//--- test CPU calculation
for(int j=0; j<TOTAL_ARRAYS; j++)
{
//--- calculation of the array with index j
Test_CPU(DataArray1,ARRAY_SIZE,j,TOTAL_ARRAYS);
}
//--- prepare CLExecute params
uint offset[]={0};
//--- global work size
uint work[]={TOTAL_ARRAYS};
//--- write data to OpenCL buffer
CLBufferWrite(cl_mem,DataArray2);
//--- execute OpenCL kernel
CLExecute(cl_krn,1,offset,work);
//--- read data from OpenCL buffer
CLBufferRead(cl_mem,DataArray2);
//--- total error
double total_error=0;
//--- compare results and calculate error
for(int j=0; j<TOTAL_ARRAYS; j++)
{
//--- calculate local offset for jth array
uint local_offset=j*ARRAY_SIZE;
//--- compare the results
for(int i=0; i<ARRAY_SIZE; i++)
{
double v1=DataArray1[i+local_offset];
double v2=DataArray2[i+local_offset];
double delta=MathAbs(v2-v1);
total_error+=delta;
//--- show first and last arrays
if((j==0) || (j==TOTAL_ARRAYS-1))
PrintFormat("array %d of %d, element [%d]: %f, %f, [error]=%f",j+1,TOTAL_ARRAYS,i,v1,v2,delta);
}
}
PrintFormat("Total error: %f",total_error);
//--- delete OpenCL objects
//--- free OpenCL buffer
CLBufferFree(cl_mem);
//--- free OpenCL kernel
CLKernelFree(cl_krn);
//--- free OpenCL program
CLProgramFree(cl_prg);
//--- free OpenCL context
CLContextFree(cl_ctx);
//---
return(0);
}
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