Lecture 2 – Threads - many-core.group

GPU strategy 1 – kernel
// find i and j indices of this thread
ti = threadIdx.x;
tj = threadIdx.y;
i = blockIdx.x*(NI_TILE) + ti;
j = blockIdx.y*(NJ_TILE) + tj;
// find indices into linear memory
i00 = I2D(ni, i, j);
im10 = I2D(ni, i-1, j); ...
// check that compute is required for this thread
if (i > 0 && i < ni-1 && j > 0 && j < nj-1) {
// evaluate derivatives
d2tdx2 = temp_in[im10] - 2*temp_in[i00] + temp_in[ip10];
d2tdy2 = temp_in[i0m1] - 2*temp_in[i00] + temp_in[i0p1];
// update temperature
temp_out[i00] = temp_in[i00] + tfac*(d2tdx2 + d2tdy2);
}