for each color/parity do
 Load the potential with opposite color/parity into a texture in the GPU.
for all     do
Given a trace with given and , calculate and set :
Fetch from the texture and put in shared memory.
if     then
   Fetch from the texture.
else
    .
end if
   Fetch from the texture.
   Calculate Laplace stencil and update the potential for the current color/parity.
end for
end for
Algorithm 1: Algorithm for the stencil on a GPU.