This article, the sixth in a series, describes a radically different technique for computing velocity from vorticity, one of the cornerstones of the fluid simulation presented in these articles. The first article summarized fluid dynamics; the second surveyed fluid simulation techniques; and the third and fourth presented a vortex-particle fluid simulation with two-way fluid-body interactions that runs in real time. The fifth article demonstrated how to obtain and use CPU usage profiling data to optimize and further parallelize the code so that it ran faster.
This article describes a differential technique for solving velocity from vorticity and contrasts its results and performance with the integral treecode technique presented in Part 3. The Poisson solver presented in this article runs faster than the treecode, but its results look different - and are potentially less satisfying.
