///
public override void LearnAttributeToFactorMapping()
{
this.factor_bias = new float[num_factors];
for (int i = 0; i < num_factors; i++)
{
factor_bias[i] = MatrixExtensions.ColumnAverage(item_factors, i);
Console.Error.WriteLine("fb {0}: {1}", i, factor_bias[i]);
}
this.attribute_to_factor = new Matrix <float>(NumItemAttributes, num_factors);
MatrixExtensions.InitNormal(attribute_to_factor, InitMean, InitStdDev);
for (int i = 0; i < num_iter_mapping; i++)
{
IterateMapping();
}
_MapToLatentFactorSpace = Utils.Memoize <int, float[]>(__MapToLatentFactorSpace);
}