static void prepare_starting_region(region * r)
{
int n, t;
double p;
assert(r->land);
/* population between 30% and 60% of max */
p = rng_double();
n = (int)(r->terrain->size * (0.3 + p * 0.3));
rsetpeasants(r, n);
/* trees: don't squash the peasants, and at least 5% should be forrest */
t = (rtrees(r, 2) + rtrees(r, 1) / 2) * TREESIZE;
if (t < r->terrain->size / 20 || t + n > r->terrain->size) {
double p2 = 0.05 + rng_double() * (1.0 - p - 0.05);
int maxtrees = (int)(r->terrain->size / 1.25 / TREESIZE); /* 1.25 = each young tree will take 1/2 the space of old trees */
int trees = (int)(p2 * maxtrees);
rsettrees(r, 2, trees);
rsettrees(r, 1, trees / 2);
rsettrees(r, 0, trees / 4);
}
/* horses: between 1% and 2% */
p = rng_double();
rsethorses(r, (int)(r->terrain->size * (0.01 + p * 0.01)));
if (!markets_module()) {
fix_demand(r);
}
}
/* NormalRand aus python, random.py geklaut, dort ist Referenz auf
* den Algorithmus. mu = Mittelwert, sigma = Standardabweichung.
* http://de.wikipedia.org/wiki/Standardabweichung#Diskrete_Gleichverteilung.2C_W.C3.BCrfel
*/
double normalvariate(double mu, double sigma)
{
static const double NV_MAGICCONST = 1.7155277699214135; /* STATIC_CONST: a constant */
double z;
for (;;) {
double u1 = rng_double();
double u2 = 1.0 - rng_double();
z = NV_MAGICCONST * (u1 - 0.5) / u2;
if (z * z / 4.0 <= -log(u2)) {
break;
}
}
return mu + z * sigma;
}
int ntimespprob(int n, double p, double mod)
{
int count = 0;
int i;
for (i = 0; i < n && p > 0; i++) {
if (rng_double() < p) {
count++;
p += mod;
}
}
return count;
}
void plagues(region * r)
{
int peasants;
int i;
int dead = 0;
peasants = rpeasants(r);
dead = (int)(0.5 + PLAGUE_VICTIMS * peasants);
for (i = dead; i != 0; i--) {
if (rng_double() < PLAGUE_HEALCHANCE && rmoney(r) >= PLAGUE_HEALCOST) {
rsetmoney(r, rmoney(r) - PLAGUE_HEALCOST);
--dead;
}
}
if (dead > 0) {
message *msg = add_message(&r->msgs, msg_message("pest", "dead", dead));
msg_release(msg);
deathcounts(r, dead);
rsetpeasants(r, peasants - dead);
}
}
double
Runif::runif(double min_val, double max_val) const {
return min_val + rng_double(state)*(max_val - min_val);
}
bool chance(double x)
{
if (x >= 1.0)
return true;
return rng_double() < x;
}