There's a lot of stuff to be suspicious of with this... A 7 point stencil is 1st order which is not likely to be very useful in the real world. If it was 1st or

There's a lot of stuff to be suspicious of with this... A 7 point stencil is 1st order which is not likely to be very useful in the real world. If it was 1st order FVM it might be more useful because at least that is conservative. I also don't buy that 50% of time is spent setting up the linear equations. They say that that is a conservative estimate; I would say that it's unrealistic - in the CFD code base I work on, it's much much less than that - about 30%, and that's when the linear solver is well parallelised and the equation set up is not.