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Make damage() use roundavg()

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Turns damage() into a one-liner.

damage() now uses random() % 32768 in chance() instead of random() %
100 inline, therefore can round differently for the same pseudo-random
number.  Update expected smoke test results accordingly.

Aside: "random() % n" distributes evenly only when n is a power of
two.  100 isn't.  However, because random() yields at least 31 bits,
and 100 is so much smaller than 2^31, the error is vanishingly small.
This commit is contained in:
Markus Armbruster 2012-08-14 21:51:22 +02:00
parent 5bf310e6b0
commit c53158eee0
2 changed files with 5 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

9
src/lib/subs/damage.c
View file

@ -163,16 +163,9 @@ nukedamage(struct nchrstr *ncp, int range, int airburst)
int
damage(int amt, int pct)
{
int tmp;
int lost;
if (amt <= 0)
return 0;
tmp = amt * pct;
lost = tmp / 100;
if (roll0(100) < tmp % 100)
lost++;
return amt - lost;
return amt - roundavg(amt * (pct / 100.0));
}
/* asymptotic damage to commodities, efficiency, and sectors */

8
tests/smoke/smoke.out
View file

@ -11969,7 +11969,7 @@ CENSUS del dst
5,-1 h 100% 127 .. .. 740 5 0 0 100% 188 0 1
7,-1 = 100% 127 .. .. 100 0 0 0 100% 59 0 1
9,-1 = 100% 127 .. .. 100 0 0 0 100% 59 0 1
11,-1 ) 91% 111 .. 0. 910 25 1 0 100% 552 0 1
11,-1 ) 91% 112 .. 0. 910 25 1 0 100% 551 0 1
-2,0 j 100% 127 .. .. 1000 0 0 0 100% 0 0 1
0,0 m 100% 127 .. .. 1000 0 0 0 100% 0 0
2,0 m 100% 127 .. 5. 999 0 579 0 100% 0 0
@ -12220,7 +12220,7 @@ You have two new telegrams waiting ...
[0:637] Command : Thu Jan 1 00:00:00 1970
CENSUS del dst
sect eff prd mob uf uf old civ mil uw food work avail ter fall coa
-6,-4 f 94% 119 .. .. 722 52 0 0 100% 457 0 1
-6,-4 f 94% 119 .. .. 722 52 0 0 100% 458 0 1
-4,-4 -o 95% 121 .. .. 730 0 0 0 100% 476 0 1
0,-4 k 100% 127 .. .. 769 0 0 0 100% 1 0 1
-5,-3 o 100% 127 .. .. 769 0 0 0 100% 0 0 1
@ -12391,7 +12391,7 @@ own sect eff prd mob uf uf old civ mil uw food work avail fall coa
1 7,-15 % 100% 118 .. .. 770 0 0 0 100% 343 0 1
1 9,-15 t 100% 123 .. .. 770 0 0 0 100% 359 0 1
1 11,-15 l 100% 122 .. .. 769 0 0 0 100% 149 0 1
8 17,-15 f 94% 119 .. .. 722 52 0 0 100% 457 0 1
8 17,-15 f 94% 119 .. .. 722 52 0 0 100% 458 0 1
8 19,-15 -o 95% 121 .. .. 730 0 0 0 100% 476 0 1
8 23,-15 k 100% 127 .. .. 769 0 0 0 100% 1 0 1
1 4,-14 b 100% 127 .. .. 1000 0 0 0 100% 299 0 1
@ -12400,7 +12400,7 @@ own sect eff prd mob uf uf old civ mil uw food work avail fall coa
1 10,-14 h 100% 127 .. .. 740 5 0 0 100% 188 0 1
1 12,-14 = 100% 127 .. .. 100 0 0 0 100% 59 0 1
1 14,-14 = 100% 127 .. .. 100 0 0 0 100% 59 0 1
1 16,-14 ) 91% 111 .. 0. 910 25 1 0 100% 552 0 1
1 16,-14 ) 91% 112 .. 0. 910 25 1 0 100% 551 0 1
8 18,-14 o 100% 127 .. .. 769 0 0 0 100% 0 0 1
8 20,-14 - 100% 127 .. .. 769 0 0 0 100% 500 0 1
8 22,-14 ! 100% 127 .. .. 769 0 0 0 100% 474 0 1