private static bool AllowWeight(int weight, GeneratorArgs args)
{
double threshold = 0;
switch (args.Balance)
{
case 0: return true;
case -1:
threshold = int.MaxValue / Math.Pow(weight, args.ExponentK);
break;
case 1:
threshold = int.MaxValue / Math.Pow(args.MaxWeight - weight + 1, args.ExponentK);
break;
default:
throw new ArgumentException("This should never happen.");
}
return threshold >= random.Next();
}
private static bool AllowWeight(int weight, GeneratorArgs args)
{
double threshold = 0;
switch (args.Balance)
{
case 0: return(true);
case -1:
threshold = int.MaxValue / Math.Pow(weight, args.ExponentK);
break;
case 1:
threshold = int.MaxValue / Math.Pow(args.MaxWeight - weight + 1, args.ExponentK);
break;
default:
throw new ArgumentException("This should never happen.");
}
return(threshold >= random.Next());
}
public static int GenerateInstance(GeneratorArgs args, int[] weights, int[] costs)
{
var issuedWeights = new int[args.MaxWeight + 1];
int i = 0, totalWeight = 0;
while (i < args.ItemsCount)
{
int weight = random.Next(1, args.MaxWeight + 1);
if (issuedWeights[weight] > 0)
continue; // already have an item with this weight
if (AllowWeight(weight, args))
{
costs[i] = issuedWeights[weight] = random.Next(1, args.MaxCost + 1);
weights[i] = weight;
totalWeight += weight;
i++;
}
}
return totalWeight;
}
public static int GenerateInstance(GeneratorArgs args, int[] weights, int[] costs)
{
var issuedWeights = new int[args.MaxWeight + 1];
int i = 0, totalWeight = 0;
while (i < args.ItemsCount)
{
int weight = random.Next(1, args.MaxWeight + 1);
if (issuedWeights[weight] > 0)
{
continue; // already have an item with this weight
}
if (AllowWeight(weight, args))
{
costs[i] = issuedWeights[weight] = random.Next(1, args.MaxCost + 1);
weights[i] = weight;
totalWeight += weight;
i++;
}
}
return(totalWeight);
}
