/// <summary>
/// 初始化一个<see cref="RandomBuilder"/>类型的实例
/// </summary>
/// <param name="seed">种子数</param>
public RandomBuilder(int seed)
{
_random = new Random(seed);
}
protected Tuple <int, int, int> SampleItemPair(int userId, Hashtable itemsTable, int[] itemIds, Core.Random random)
{
// an item rated by a user
int itemId = itemIds[random.Next(itemIds.Length)];
while (!itemsTable.ContainsKey(itemId))
{
itemId = itemIds[random.Next(itemIds.Length)];
}
// an item which has not been rated by a user
int otherItemId = itemIds[random.Next(itemIds.Length)];
while (itemsTable.ContainsKey(otherItemId))
{
otherItemId = itemIds[random.Next(itemIds.Length)];
}
return(Tuple.Create(userId, itemId, otherItemId));
}
/// <summary>
/// 初始化一个<see cref="RandomBuilder"/>类型的实例
/// </summary>
public RandomBuilder()
{
_random = new Random();
}
protected int SampleOtherItemId(int userId, Hashtable itemsTable, int[] itemIds, Core.Random random)
{
// an item which has not been rated by a user
int otherItemId = itemIds[random.Next(itemIds.Length)];
while (itemsTable.ContainsKey(otherItemId))
{
otherItemId = itemIds[random.Next(itemIds.Length)];
}
return(otherItemId);
}
