[Freeciv-Dev] Re: flying AI (PR#1162)

[Petr Baudis <pasky@xxxxxxxxxxx>]

Dear diary, on Sat, Dec 29, 2001 at 07:40:18AM CET, I got a letter,
where Raahul Kumar <raahul_da_man@xxxxxxxxx> told me, that...
> Some additional titbits for you. Hope this makes the function clearer.
> I strongly suspect you want me to explain the 
> 
> else b0 = ((b * a - f * d) * SHIELD_WEIGHTING / (a + d)) - 
> 1412 c * (unhap ? SHIELD_WEIGHTING + 2 * TRADE_WEIGHTING : SHIELD_WEIGHTING);
> 
> Sorry. I'm still trying to figure out the behaviour of amortise myself.
> Will send in  a patch sometime next century when I figure out what the
> hell Syela was thinking. Basic summary of amortise - we figure out what
> the effect of unhappiness will be from building this unit, affect on 
> trade(only
> matters for caravans/freights), the shield weighting( to prevent cities
> building
> one more unit that exhausts all shields). Unfortunately, the devil is in the
> details. 

I didn't find that line anywhere, however Syela use very similiar formulas
here. So let's have a look at a bit different version of this ;-).

First, original version, so that we can find similiarity with the above:

      else {
        b0 = (b * a - (f + (acity ? acity->ai.f : 0)) * d) * g * 
SHIELD_WEIGHTING / (a + g * d);
        if (acity && b * acity->ai.a * acity->ai.a > acity->ai.f * d)
          b0 -= (b * acity->ai.a * acity->ai.a - acity->ai.f * d) *
                           g * SHIELD_WEIGHTING / (acity->ai.a * acity->ai.a + 
g * d);
      }
      if (b0 > 0) {
        b0 -= l * SHIELD_WEIGHTING;
        b0 -= c * (unhap ? SHIELD_WEIGHTING + 2 * TRADE_WEIGHTING : 
SHIELD_WEIGHTING);
      }

and a bit more coder-friendly version:

      } else {
        desire = (value * attack - (build_cost + (acity ? acity->ai.f : 0)) * 
resist) * protect * SHIELD_WEIGHTING /
                 (attack + protect * resist);

        if (acity && value * acity->ai.a * acity->ai.a > acity->ai.f * resist)
          desire -= (value * acity->ai.a * acity->ai.a - acity->ai.f * resist) *
                    protect * SHIELD_WEIGHTING / (acity->ai.a * acity->ai.a + 
protect * resist);
      }

      if (desire > 0) {
        desire -= tech_cost * SHIELD_WEIGHTING;
        desire -= move_cost * (unhap ? SHIELD_WEIGHTING + 2 * TRADE_WEIGHTING : 
SHIELD_WEIGHTING);
      }

Sorry, but I've currently no time to explain this more, as I must go outdoors
now ;p. However you are welcome to have a look at CVS to see how are these
values initialized (so what they mean), send me some comments patches etc ;-).

-- 

                                Petr "Pasky" Baudis

UN*X programmer, UN*X administrator, hobbies = IPv6, IRC, FreeCiv, (e)links
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