Re: Major bug and what to do about it (long)

[Eric McDonald <mcdonald at phy dot cmich dot edu>]

On Wed, 18 Aug 2004, Hans Ronne wrote:

> >But, this is where we differ, I think. The shell has to land somewhere,
> >and it is possible that _no_ unit sits where it lands.
> 
> Of course. And it is also possible that the target unit is entrenched,
> protected by other units or the terrain, 

Protection is already handled by other tables, and doesn't factor 
into this argument, I think.

> I do understand the "Unit target area" scheme that you are proposing, or at
> least I think so. You would calculate how much of the total area is
> covered, and then use that to distribute hit-chances between the units and
> the empty area. 

That is essentially correct.

> I see random firing of a gun into a terrain area as a statistical process
> in two space dimesions (we need not consider time here). The key aspect of
> this process is that the position of each hit is independent of both
> previous and coming hits. This means that a given unit (or subarea) has a
> fixed probability of being hit with each shot. This probability may depend
> on the unit's size, its protection, the terrain and many other factors. The
> probability may be anything from 0% to 100%.

What I think you are saying is that the 'hit-chance' or 
'fire-hit-chance' probabilities apply against the entire space of 
the cell and not against the local region that the unit is 
located.

> Furthermore, it is important that the dice rolling is done in a random
> order, since we would otherwise favour hits of units at the top of the
> stack, particularly when each unit has a high hit-chance.

Sure. Of course.

> I hope this clarified my views.

Your argument was well made, and for a couple of minutes almost 
had me believing that apples were oranges. However, apples are 
still not oranges, and here's why:

According to you, if I understand you correctly and I think I 
do, the hit chance applies to the unit as it relates 
to the space of the entire cell and not to the localized region 
("subarea", as you called it) where the unit is located. Now this 
means that if I do a 'fire-into' on a cell that has an unseen unit 
unit of type "u1", then the probability of hitting it is 
determined by its hit chance (and any modifiers to that). So, assuming no 
modifiers on the hit chance, and assuming that type "u1" has a 75% 
chance of being hit by type "u2", type "u2" being the type which 
is firing, then there is 75% that the unseen unit, "u1", will be 
hit.

So far, so good. Now, to throw the wrench. Now suppose that "u1" 
is seen, and "u2" does a 'fire-at' on "u1". Again, the probability 
is 75% that "u1" will be hit.   Ooops, no good.

The problem here is that 'fire-at' assumes that the target is 
being aimed at and applies the hit chance on this assumption. 
Then, you are coming along, and claiming a different 
interpretation of the hit chance when it is being used by 
'fire-into', where aiming is no longer being considered. We must 
be able to differentiate between the two cases.

I see two ways out:
(1) Assume that 'fire-at' has a 100% hit chance and apply any 
modifiers to that chance. This is, however, inconsistent with the 
way attack works, and makes little sense, IMO.
(2) Use the method I proposed.

Maybe there are others, but these are the two that I see.

Eric