I’m currently running dwi2response on a HCP diffusion dataset (~3,9 GB file, 1000, 2000, 3000 and b0, 90 directions for each non b0 shell). When I use the debug flag I am informed that one of the first steps is to mrconvert (and therefore copy) the file to the temporary directory with a -strides 0,0,0,1 option.
This takes very very long and I wonder why. Can someone explain this to me? Is the data somehow rearranged in memory to make later computations faster? Is there a way to speed things up?