public GenericDataModel(FastByIDMap <PreferenceArray> userData, FastByIDMap <FastByIDMap <DateTime?> > timestamps)
{
this.preferenceFromUsers = userData;
FastByIDMap <List <Preference> > data = new FastByIDMap <List <Preference> >();
FastIDSet set = new FastIDSet();
int num = 0;
float negativeInfinity = float.NegativeInfinity;
float positiveInfinity = float.PositiveInfinity;
foreach (KeyValuePair <long, PreferenceArray> pair in this.preferenceFromUsers.entrySet())
{
PreferenceArray array = pair.Value;
array.sortByItem();
foreach (Preference preference in array)
{
long key = preference.getItemID();
set.add(key);
List <Preference> list = data.get(key);
if (list == null)
{
list = new List <Preference>(2);
data.put(key, list);
}
list.Add(preference);
float num5 = preference.getValue();
if (num5 > negativeInfinity)
{
negativeInfinity = num5;
}
if (num5 < positiveInfinity)
{
positiveInfinity = num5;
}
}
if ((++num % 0x2710) == 0)
{
log.info("Processed {0} users", new object[] { num });
}
}
log.info("Processed {0} users", new object[] { num });
this.setMinPreference(positiveInfinity);
this.setMaxPreference(negativeInfinity);
this.itemIDs = set.toArray();
set = null;
Array.Sort <long>(this.itemIDs);
this.preferenceForItems = toDataMap(data, false);
foreach (KeyValuePair <long, PreferenceArray> pair in this.preferenceForItems.entrySet())
{
pair.Value.sortByUser();
}
this.userIDs = new long[userData.size()];
int num6 = 0;
foreach (long num7 in userData.Keys)
{
this.userIDs[num6++] = num7;
}
Array.Sort <long>(this.userIDs);
this.timestamps = timestamps;
}
public double userSimilarity(long userID1, long userID2)
{
int num4;
PreferenceArray array = this.dataModel.getPreferencesFromUser(userID1);
PreferenceArray array2 = this.dataModel.getPreferencesFromUser(userID2);
int num = array.length();
int num2 = array2.length();
if ((num <= 1) || (num2 <= 1))
{
return(double.NaN);
}
array = array.clone();
array2 = array2.clone();
array.sortByValue();
array2.sortByValue();
float num3 = 1f;
for (num4 = 0; num4 < num; num4++)
{
if (array2.hasPrefWithItemID(array.getItemID(num4)))
{
array.setValue(num4, num3);
num3++;
}
}
num3 = 1f;
for (num4 = 0; num4 < num2; num4++)
{
if (array.hasPrefWithItemID(array2.getItemID(num4)))
{
array2.setValue(num4, num3);
num3++;
}
}
array.sortByItem();
array2.sortByItem();
long num5 = array.getItemID(0);
long num6 = array2.getItemID(0);
int i = 0;
int num8 = 0;
double num9 = 0.0;
int num10 = 0;
while (true)
{
int num11 = (num5 < num6) ? -1 : ((num5 > num6) ? 1 : 0);
if (num11 == 0)
{
double num12 = array.getValue(i) - array2.getValue(num8);
num9 += num12 * num12;
num10++;
}
if (num11 <= 0)
{
if (++i >= num)
{
break;
}
num5 = array.getItemID(i);
}
if (num11 >= 0)
{
if (++num8 >= num2)
{
break;
}
num6 = array2.getItemID(num8);
}
}
if (num10 <= 1)
{
return(double.NaN);
}
return(1.0 - ((6.0 * num9) / ((double)(num10 * ((num10 * num10) - 1)))));
}
