OpenCL kernel parameters

Question

I am new in OpenCL. I want to tranfer a type int parameter in the kernel to do the operations, but I don't know how to do this. I have only worked with vectors and matrix, but I have never transfer an atribute.

If I have this code example below:

typedef struct{
  int fila;
  int columna;
  int value; 
}Matrix;

int main(){

  Matrix matrix;
  matrix.row = 56;
  matrix.column = 64;
  matrix.value = 0;
  float A[matrix.fila][matrix.columna];
}

In the kernel:

__kernel void matrix(__global int vue) {
     value = value + 10; //it is only an example
}

Can I do that operation above of "matrix.valor" (value + 10) in the kernel?? Or it is only for vectors and matrix operations? Do I need cl_mem or it is not necessary? I'am currently lost with this.

Dithermaster Dithermaster · Accepted Answer · 2017-08-24T04:32:36

Remove the __global from the kernel parameter. Then, in your C/C++ code, have a variable of type cl_int (declared in cl.h) and set it to the value you want to pass into the kernel. Before enqueing the kernel (with clEnqueueNDRangeKernel) call clSetKernelArg with parameters of your kernel, the parameter index (0), sizeof(cl_int), and the address of your variable (e.g., clSetKernelArg(myKernel, 0, sizeof(cl_int), &myVariable).

Here is the documentation for clSetKernelArg. Also, search for just about any piece of OpenCL sample code.

OpenCL kernel parameters

1 Answers