should loop over union of two sets of integrals:
set 1:
i<=k
j<=l
ik<=jl
set 2:
i>k
j<l
ik<=jl
looping over kpts in same way is incorrect
here I've relaxed the constraints over kpt indices, while keeping those over orbital indices
There is probably a more efficient way to do this where we have more kpt constraints and additional logic in orbital loops
