GfsOutputParticle
From Gerris
GfsOutputParticle tracks particles moving with the velocity of the fluid (pathlines).
The syntax is:
[ [GfsOutput|GfsOutput] ] x0 y0 z0
where (x0,y0,z0) define the initial position of the particle. The motion of the particle is recorded in the file 'filename' with the format (t, x, y, z).

