///
public override void LearnAttributeToFactorMapping()
{
// create attribute-to-latent factor weight matrix
this.attribute_to_factor = new Matrix <float>(NumItemAttributes + 1, num_factors);
// store the results of the different runs in the following array
var old_attribute_to_factor = new Matrix <float> [num_init_mapping];
Console.Error.WriteLine("Will use {0} examples ...", num_iter_mapping * MaxItemID);
var old_rmse_per_factor = new double[num_init_mapping][];
for (int h = 0; h < num_init_mapping; h++)
{
MatrixExtensions.InitNormal(attribute_to_factor, InitMean, InitStdDev);
Console.Error.WriteLine("----");
for (int i = 0; i < num_iter_mapping * MaxItemID; i++)
{
IterateMapping();
}
old_attribute_to_factor[h] = new Matrix <float>(attribute_to_factor);
old_rmse_per_factor[h] = ComputeMappingFit();
}
var min_rmse_per_factor = new double[num_factors];
for (int i = 0; i < num_factors; i++)
{
min_rmse_per_factor[i] = Double.MaxValue;
}
var best_factor_init = new int[num_factors];
// find best factor mappings
for (int i = 0; i < num_init_mapping; i++)
{
for (int j = 0; j < num_factors; j++)
{
if (old_rmse_per_factor[i][j] < min_rmse_per_factor[j])
{
min_rmse_per_factor[j] = old_rmse_per_factor[i][j];
best_factor_init[j] = i;
}
}
}
// set the best weight combinations for each factor mapping
for (int i = 0; i < num_factors; i++)
{
Console.Error.WriteLine("Factor {0}, pick {1}", i, best_factor_init[i]);
attribute_to_factor.SetColumn(i,
old_attribute_to_factor[best_factor_init[i]].GetColumn(i)
);
}
_MapToLatentFactorSpace = Utils.Memoize <int, float[]>(__MapToLatentFactorSpace);
}
///
public override void LearnAttributeToFactorMapping()
{
// create attribute-to-factor weight matrix
attribute_to_factor = new Matrix <float>(NumUserAttributes, num_factors);
Console.Error.WriteLine("\nBPR-OPT-USERMAP training");
Console.Error.WriteLine("num_user_attributes=" + NumUserAttributes);
MatrixExtensions.InitNormal(attribute_to_factor, InitMean, InitStdDev);
for (int i = 0; i < num_iter_mapping; i++)
{
IterateMapping();
}
}
///
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);
}
void LearnItemAttributeToFactorMapping()
{
// no mapping of no item attributes present
if (item_attributes.NumberOfEntries == 0)
{
return;
}
// create attribute-to-latent factor weight matrix
this.item_attribute_to_factor = new Matrix <float>(NumItemAttributes + 1, num_factors);
// store the results of the different runs in the following array
var old_attribute_to_factor = new Matrix <float> [num_init_mapping];
//Console.Error.WriteLine("Will use {0} examples ...", num_iter_mapping * MaxItemID);
var old_rmse_per_factor = new double[num_init_mapping][];
for (int h = 0; h < num_init_mapping; h++)
{
MatrixExtensions.InitNormal(item_attribute_to_factor, InitMean, InitStdDev);
Console.Error.WriteLine("----");
for (int i = 0; i < num_iter_mapping * MaxItemID; i++)
{
UpdateItemMapping();
}
old_attribute_to_factor[h] = new Matrix <float>(item_attribute_to_factor);
old_rmse_per_factor[h] = ComputeItemMappingFit();
}
var min_rmse_per_factor = new double[num_factors];
for (int i = 0; i < num_factors; i++)
{
min_rmse_per_factor[i] = Double.MaxValue;
}
var best_factor_init = new int[num_factors];
// find best factor mappings
for (int i = 0; i < num_init_mapping; i++)
{
for (int j = 0; j < num_factors; j++)
{
if (old_rmse_per_factor[i][j] < min_rmse_per_factor[j])
{
min_rmse_per_factor[j] = old_rmse_per_factor[i][j];
best_factor_init[j] = i;
}
}
}
// set the best weight combinations for each factor mapping
for (int i = 0; i < num_factors; i++)
{
Console.Error.WriteLine("Factor {0}, pick {1}", i, best_factor_init[i]);
item_attribute_to_factor.SetColumn(i,
old_attribute_to_factor[best_factor_init[i]].GetColumn(i)
);
}
ComputeFactorsForNewItems();
}
