/*
* Sphere Search is done iteratively in “Spheres” and is used to attempt to trace a path
* from the beginning to the end of the game. The first sphere s is simply all locations which are
* reachable from the beginning of the game. As it searches these locations, it adds key items
* found to a temporary set; we do not want those items to affect reachability until the next sphere
* iteration so we do not yet add them to I. After all reachable locations have been found, sphere s
* is added to the list of spheres S, and all items in the temporary set are added to I. It then
* iterates again with a new sphere s.
*/
public SphereSearchInfo SphereSearch(WorldGraph world)
{
SphereSearchInfo output = new SphereSearchInfo();
output.Spheres = new List <WorldGraph>();
List <Item> owneditems = new List <Item>();
//Initial sphere s0 includes items reachable from the start of the game
WorldGraph s0 = GetReachableLocations(world, owneditems);
owneditems = s0.CollectMajorItems(); //Collect all major items reachable from the start of the game
output.Spheres.Add(s0); //Add initial sphere to sphere list
//sx indicates every sphere after the first. Any major items found in s0 means sx should be bigger.
WorldGraph sx = GetReachableLocations(world, owneditems);
int temp = owneditems.Where(x => x.Importance >= 2).Count(); //Temp is the count of previously owned major items
owneditems = sx.CollectAllItems(); //Used to find new count of major items
//If counts are equal then no new major items found, stop searching
while (owneditems.Where(x => x.Importance >= 2).Count() > temp) //If new count is not greater than old count, that means all currently reachable locations have been found
{
output.Spheres.Add(sx); //If new locations found, add to sphere list
//Take the same steps taken before the loop: Get new reachable locations, collect new major items, and check to see if new count is larger than old count
sx = GetReachableLocations(world, owneditems);
temp = owneditems.Where(x => x.Importance >= 2).Count(); //Only want to consider count of major items
owneditems = sx.CollectAllItems();
}
//At this point, either a dead end has been found or all locations have been discovered
//If the goal item is in the list of owned items, means the end has been found and thus the game is completable
output.Completable = owneditems.Count(x => x.Name == world.GoalItemName) > 0;
return(output);
}
//Calculates the bias for a given permutation of items in the world graph
public BiasOutput CalcDistributionBias(WorldGraph world)
{
//Get total counts for majors and items so a percent can be calculated
int totalmajorcount = world.Items.Where(x => x.Importance >= 2).Count();
int totallocationcount = world.GetLocationCount();
//Find spheres in randomized world
Search searcher = new Search();
List <WorldGraph> spheres = searcher.SphereSearch(world).Spheres;
//Initialize variables to use in the loop
double[] spherebias = new double[spheres.Count];
int rollingmajorcount = 0;
int rollinglocationcount = 0;
for (int i = 0; i < spheres.Count; i++)
{
WorldGraph sphere = spheres[i];
//Check the number of major items in the sphere, not counting those in previous spheres
int majoritemcount = sphere.CollectMajorItems().Count - rollingmajorcount;
rollingmajorcount += majoritemcount;
//Check the number of locations in the sphere, not counting those in previous spheres
int locationcount = sphere.GetLocationCount() - rollinglocationcount;
rollinglocationcount += locationcount;
//Find the percentage of major items and locations in this sphere
double majorpercent = majoritemcount / (double)totalmajorcount;
double locationpercent = locationcount / (double)totallocationcount;
//Now find the difference between the two percentages
double difference = majorpercent - locationpercent;
spherebias[i] = difference;
}
//Now that we have a list of biases find the sum of their absolute values to determine absolute bias
//Also use the positivity of bias before and after the median to determine bias direction
double overallsum = 0;
double beforesum = 0; //Sums bias before median so a bias direction can be computed
double aftersum = 0; //Sums bias after median so a bias direction can be computed
bool even = spherebias.Length % 2 == 0; //Want to check if even so can determine when after the median is
int median = spherebias.Length / 2; //Use median to determine bias direction
for (int i = 0; i < spherebias.Length; i++)
{
overallsum += Math.Abs(spherebias[i]);
if (i < median) //Before median, add to that sum
{
beforesum += spherebias[i];
}
else if ((i >= median && even) || (i > median && !even)) //After median, add to that sum. If it's even then >= makes sense so every index is checked, if odd then skip middle
{
aftersum = spherebias[i];
}
}
//Package output and return
BiasOutput output = new BiasOutput();
output.biasvalue = overallsum / spherebias.Length; //Get average of absolute value to determine overall bias
output.direction = beforesum < aftersum; //If bias is more positive before the median, the direction is toward the beginning, otherwise toward end
return(output);
}
