Results 1 to 2 of 2

Thread: I beg u plzzz ,I really need help with this open cl code

  1. #1
    Junior Member
    Join Date
    Oct 2012

    I beg u plzzz ,I really need help with this open cl code

    I recently wrote this kernel in open cl,which is working well and returning correct results.

    Code :
    spmv_csr_scalar_kernel(const int num_rows,
                           const int * ptr,
                           const int * indices,
                           const float * data,
                           const float * x,
                           float * y )
        int row = get_global_id(0);
        if(row < num_rows)
            float dot = 0;
            int row_start = ptr[row];
            int row_end = ptr[row+1];
            for (int jj = row_start; jj < row_end; jj++)
                dot += data[jj] * x[indices[jj]];
            y[row] += dot;

    It is multiplication of a sparse matrix in compressed row storage with a column vector.It returns correct result.Uses one work item for each for loop (from row_start to row_end).

    I want to convert the above code to using two work items per single for loop.But I am getting incorrect is what I could come write.

    Code :
    __kernel void mykernel(__global int* colvector,
                           __global int* val,
                           __global int* result,
                           __global int* index,
                           __global int* rowptr,
                           __global int* sync )
        __global int vals[8]={0,0,0,0,0,0,0,0};
        for(int i=0;i<4;i++)
        int thread_id=get_global_id(0);
        int warp_id=thread_id/2;
        int lane=(thread_id)&1;
        int row=warp_id;
            int row_start = rowptr[row];
            int row_end = rowptr[row+1];
            for (int i = row_start+lane; i<row_end; i+=2)
                result[row] += vals[thread_id];

    Can anybody help me plzzzzz?My deadline is tomorrow and its returning incorrect results.

  2. #2
    Senior Member
    Join Date
    Aug 2011

    Re: I beg u plzzz ,I really need help with this open cl code

    Is this homework or for marked study?

Similar Threads

  1. OpenCL compression code running 10 times than serial code !!
    By satyajitdeshmukh in forum OpenCL - parallel programming of heterogeneous systems
    Replies: 1
    Last Post: 12-06-2010, 09:39 AM
  2. Open GL and Open VG rendering on the same EGL surface
    By ajay in forum EGL - native graphics platform interface
    Replies: 4
    Last Post: 01-15-2009, 12:19 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts