update a single box is therefore the sum of two Hermite evaluations (one for each dimension), plus the powers of $\delta/\delta_j$, the weights and the final sum, i.e.:

$$N_{\rm grid} = 2 (N_{\rm cexp} + q' + N_C[N_C + 1]) + 4(q'+1) + 3(q'+1)^2$$

For small $q'$, the cost is dominated by the cost of evaluating the complex exponential. For large $q'$, it is dominated by the multiply-add step in the final sum.

### Degridding

The operations count for the degridding process is similar to the gridding case. The order $q'$ is evaluated identically, as are the Hermite functions and the powers of $\delta/\delta_j$. The only difference is that no weight is included, and the multiply-add stage includes the product of the two hermite functions, the power and the Taylor term, requiring $4(q'+1)^2$ operations.

The number of operations per visibility is therefore: $$N_{\rm degrid} = 2(N_{\rm cexp} + q' + N_C[N_C + 1]) + 2(q'+1) + 4(q'+1)^2.$$

Once again, for small $q'$, the cost is dominated by the cost of evaluating the complex exponential. For large $q'$, it is dominated by the multiply-add step in the final sum.

### Memory bandwidth

Calculating memory bandwidth is complicated by the issue of 