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     Ends the geometry definitions.
     This option can also be used to debug the geometry: in this case
     it may extend over two cards


     Normally, only one GEOEND card is issued, at the end of the geometry
     description, with all the WHATs and the 
equal to zero or blank. However, GEOEND can also be used to activate the FLUKA geometry debugger: in this case one or two GEOEND cards are needed, providing the information described below. 1st GEOEND card:
= X_max of the geometry region to be debugged (no default)
= Y_max of the geometry region to be debugged (no default)
= Z_max of the geometry region to be debugged (no default)
= X_min of the geometry region to be debugged (no default)
= Y_min of the geometry region to be debugged (no default)
= Z_min of the geometry region to be debugged (no default)
= DEBUG to activate the debugger, otherwise must be left blank 2nd (optional) GEOEND card:
= Number of mesh intervals in the x-direction between X_min and X_max
= 20.0
= Number of mesh intervals in the y-direction between Y_min and Y_max
= 20.0
= Number of mesh intervals in the z-direction between Z_min and Z_max
= 20.0 WHAT(4,5,6) : not used
= "&" in any position in column 71 to 78 (or in the last field if free format is used)
(option GEOEND not given): not allowed! GEOBEGIN and GEOEND must always be present.
1) The geometry debugger can detect both undefined points (points which are not included in any defined region) or multiple defined points (points which are included in more than one region (i.e. there are overlapping regions) in the selected X,Y,Z mesh. The first kind of error is likely to cause a run-time error every time a particle is passing through the undefined zone, the second one is more subtle and it is not usually detected at run-time. It is impossible to predict to which actual region such multiple defined points will be assigned. 2) The geometry debugger cannot assure that a bug-free geometry input is what the user would like to describe, however it seldom occurs that users are able to define a bug-free input different from what they wanted to describe. 3) It must be stressed that only the points of the defined X,Y,Z mesh are checked, therefore mesh dimensions and pitches should be chosen according to the present geometry, taking into account region thicknesses etc. 4) Another useful tool is available for this purpose: the PLOTGEOM program, which is activated by means of the PLOTGEOM command. 5) It must be stressed too that the geometry debugger can be very time consuming, so don't ask for 100 micrometres pitches in X,Y,Z over 10 metres or the code will run forever! Make use as much as possible of geometry symmetries (for example for a cylindrical geometry there is no need for a 3-D scan) and possibly "zoom" with fine meshes only around points where you suspect possible errors. Note that as many areas as wished can be scanned with different meshes of the SAME geometry, simply changing the mesh parameters each time. 6)
the program does not stop if an error is detected but a message is issued on the output units, and checking goes on. If the code is "stepping" into an area erroneously defined, it is likely that plenty of such error messages will be printed. If your operating system allows inspection of output files before they are closed, check the size of your output from time to time. If it is growing too much, stop the code and correct the geometry for the printed errors before restarting the debugger. Example of a normal GEOEND card without debugging:
GEOEND 0. 0. 0. 0. 0. 0.
* The next is an example of geometry debugging:
GEOEND 150. 75. 220. 30. 0. -220.DEBUG GEOEND 120. 1. 110. 0. 0. 0. &
* The above cards request a scan of the geometry portion delimited
* by planes x = 30, x = 150, y = 0, y = 75, z = -220, z = 220,
* with 120 steps 1-cm wide along x, one single step along y and
* 110 4-cm wide steps along z. A single step in one direction (here y)
* is typical of searches through cylindrically symmetric geometries.

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