Looking for three horizons

The finder can also be used to look for three horizons each time. This is done by just running the algorithm three consecutive times with different initial guesses, and is useful for simulations of black hole collisions.

• ahfinder::ahf_find3
  Set ahf_find3 = "yes" to search for three horizons. The default is to look for only one horizon.
• ahfinder::ahf_[xyz]_[012] (steerable)
  Sets the x-, y-, and z-coordinates of the center of the expansion for horizon 0, 1 and 2. The default in each case is the origin.
• ahfinder::ahf_r0_[0-2] (steerable)
  Sets the radius of the initial spheres for horizon 0, 1 and 2. The default in all cases is 0.0, forcing the largest sphere possible in the grid.