/************************************************/
/*						*/
/*	Choose prey in neighbourhood to eat	*/
/*						*/
/************************************************/

void get_prey_item(menu, current)
double menu;
struct individual *current;
{
double rn;
double sum;
struct individual *prey;
	rn=drand48()*menu;

	prey=start;
	sum=0.0;

	/***Choose prey at random***/
	while(prey!=NULL){

/*printf("%lf\n", prey->eaten_event);*/

		sum+=prey->eaten_event;

		if(sum>rn)
			break;
		else
			prey=prey->next;
	}

	death(prey);
	rn=drand48();

	if(rn<conversion[current->species])
		newborn(current);

}

/************************************************/
/*						*/
/*	Weight prey in neighbourhood		*/
/*						*/
/************************************************/

void predate(current)
struct individual *current;
{
double x1, y1, x2,y2, radius;
int spp1, spp2;
struct individual *neighbour;
double menu, distance, norm, effect;

	neighbour=start;
	x1=current->xpos;
	y1=current->ypos;

	spp1=current->species;
	menu=0.0;

while(neighbour!=NULL){

	neighbour->eaten_event=0.0;

	x2=neighbour->xpos;
	y2=neighbour->ypos;
	spp2=neighbour->species;

	radius=wfoormax[spp1][spp2];

	distance = get_distance(x1,y1,x2,y2,radius);	

	if(distance<radius){
		norm=2.0*Pi*wfoostdv[spp1][spp2]*wfoostdv[spp1][spp2];
		effect=distance/wfoostdv[spp1][spp2];

		effect*=effect;
		effect=exp(-0.5*effect);
		effect/=norm;
/*	printf("%lf\t", effect*alpha[spp1][spp2]);
	printf("%d\n", neighbour->species);*/
		neighbour->eaten_event=effect*alpha[spp1][spp2];
		menu+=neighbour->eaten_event;
	}

	neighbour=neighbour->next;
	}
/*printf("Attack: %lf\n", current->attack_event);
printf("MENU: %lf\n", menu);*/

	get_prey_item(menu, current);
}