Strange Syntax

[Richard Andrew x64]

I saw this code snippet on a web page that was talking about CUDA[^] cores: Does anyone know the meaning of the syntax on the third line where they call the kernel function with those greater-than and less-than signs?

dim3 blockDim(16, 16, 1);
dim3 gridDim((width + blockDim.x - 1)/ blockDim.x, (height + blockDim.y - 1) / blockDim.y, 1);
kernel<<< gridDim, blockDim, 0 >>>(d_data, height, width);

// Unbind the array from the texture
cudaUnbindTexture(tex);
} //end foo()

__global__ void kernel(float* odata, int height, int width)
{
unsigned int x = blockIdx.x*blockDim.x + threadIdx.x;
unsigned int y = blockIdx.y*blockDim.y + threadIdx.y;
if (x < width && y < height) {
float c = tex2D(tex, x, y);
odata[y*width+x] = c;
}
}

The difficult we do right away... ...the impossible takes slightly longer.

[CPallini]

It is an extension of the NVIDIA CUDA compiler (see "Introduction to CUDA C"[^]:

Triple angle brackets mark a call from host code to device code — Sometimes called a “kernel launch”

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite

[Richard Andrew x64]

Thank you.

The difficult we do right away... ...the impossible takes slightly longer.

[CPallini]

You are welcome.

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite