The DW model is more efficient in one dimension because it can make
use of delay lines to obtain an
computation per time sample
[441], whereas the FDTD scheme is
per sample
(
being the number of spatial samples along the string). There is
apparently no known way to achieve
complexity for the FDTD
scheme. In higher dimensions, i.e., when simulating membranes and
volumes, the delay-line advantage disappears, and the FDTD scheme has
the lower operation count (and memory storage requirements).