Illustrative contents of the address array for the forward precomputed interpolation. In the inertial frame (bottom black line), knots have indices i. In the comoving frame (top black line), knots that lie on the inertial interval [i,i + 1), have indices if at least one such knot exists. For each i, corresponding memory-offset o is computed such that address[ o] points to . Orange lines indicate correspondence. Solid black lines connecting i to , indicate l.h.s. weights . There is no contribution from knot i−1, because interval [i−1,i) does not contain any comoving knots. In this case, address[ o−1] points to the knot that lies on the previous interval. We note that address keeps addresses but not the values of the shown comoving knots, those are stored in forward_j instead.