CUDA compute a general formula for thread indexing

CUDA Thread Index:

int blockid = blockidx.z * (GRIDDIM.X*GRIDDIM.Y)
+ blockidx.y * griddim.x
+ blockidx.x;

int threadId = Blockid * (blockdim.x * blockdim.y * blockdim.z)
+ threadidx.z * (blockdim.x * blockdim.y)
+ threadidx.y * blockdim.x
+ threadidx.x;

From top to bottom, respectively:

The 3,2,1 dimension of block;

The 3,2,1 dimension of thread.

If there is no corresponding dimension, delete the corresponding calculation part.

The value of the dimension is a minimum of 1, but the index has a minimum value of 0.

PS: The least case is that there are only 1 dimensions, most of which are 3 dimensions.

So the simplest of all is only 1 dimensions: blockidx.x * blockdim.x + threadidx.x

CUDA compute a general formula for thread indexing