FillUpCache Subroutine

    SUBROUTINE FillUpCache()
        ! Disperse the (pre-calculated) <ik|u|jk> integrals throughout the cache.
        ! The cache consists of an unordered set (in the standard UMatCache
        ! sense) of labels and elements.
        ! We must order this, and then distribute the elements throughout each set of SLOTS.
        INTEGER I, J, K, N, nK
        DO I = 1, nPairs
! Find the last value in the cache
            CALL BinarySearch(nPairs + 1, UMatLabels(1:nSlots, I), 1, nSlots, N, J, K)
            N = J - 1
! N is now the last element and thus number of elements.
! Sort according to label
            call sort(UMatLabels(1:N, i), UMatCacheData(:, 1:N, i))
            K = nSlots
! Now copy element among the whole array for this, from the end.
! (Multiple copies of the same integral in an unfilled cache make adding
! elements ! substantially faster.)
            DO J = N, 1, -1
                nK = (nSlots * (J - 1)) / N + 1
                UMatLabels(nK:K, I) = UMatLabels(J, I)
                DO K = K, nK, -1
                    UMatCacheData(:, K, I) = UMatCacheData(:, J, I)
                end do
                K = nK
            end do
        end do
    END SUBROUTINE FillUpCache