/// <summary>
/// Called when a scheduled job executes
/// </summary>
/// <returns>A status message to be stored in the database log and visible from admin mode</returns>
/// <exception cref="T:System.AggregateException">The exception that contains all the individual exceptions thrown on all threads.</exception>
public override string Execute()
{
this.OnStatusChanged("Starting to update/train the model");
List <ProductEntry> products = this.GetProductEntries();
ITransformer transformer = this.LoadDataAndTrain(products: products);
this.predictionEngine = new MlModelEngine <ProductEntry, CoPurchasePrediction>(transformer: transformer);
this.OnStatusChanged("Prediction model has been updated and trained");
ConcurrentBag <IProductCoPurchasePrediction> predictions = new ConcurrentBag <IProductCoPurchasePrediction>();
List <int> productIds = this.GetAllVariantIds().ToList();
this.OnStatusChanged("Creating predictions");
foreach (int productId in productIds)
{
if (this.stopSignaled)
{
break;
}
List <int> coPurchaseProductIds = productIds.Where(id => id != productId).ToList();
Parallel.ForEach(
source: coPurchaseProductIds,
coPurchaseProductId =>
{
IProductCoPurchasePrediction productCoPurchasePrediction = this.GetPrediction(
productId: productId,
coPurchaseProductId: coPurchaseProductId);
if (productCoPurchasePrediction != null)
{
predictions.Add(item: productCoPurchasePrediction);
}
});
}
try
{
this.recommendationRepository.AddOrUpdate(predictions: predictions);
}
catch (Exception exception)
{
this.log.Error(
$"[Prediction Engine] could not create predictions: {exception.Message}",
exception: exception);
return($"Could not create predictions: {exception.Message}");
}
// For long running jobs periodically check if stop is signaled and if so stop execution
return(this.stopSignaled ? "Stop of job was called" : $"Created {predictions.Count} predictions");
}
/// <summary>
/// Adds or updates <see cref="IProductCoPurchasePrediction" /> in the repository.
/// </summary>
/// <param name="productCoPurchasePrediction">The ProductCoPurchasePrediction.</param>
public virtual void AddOrUpdate(IProductCoPurchasePrediction productCoPurchasePrediction)
{
string sqlCommand =
$@"UPDATE {PredictionsTable} SET [Score] = @score WHERE [ProductId] = @productId AND [CoPurchaseProductId] = @coPurchaseProductId
IF @@ROWCOUNT = 0
INSERT INTO {PredictionsTable} ([ProductId], [CoPurchaseProductId], [Score]) VALUES (@productId, @coPurchaseProductId, @score)";
this.ExecuteNonQuery(
() => this.CreateCommand(
sqlCommand: sqlCommand,
this.CreateIntParameter("productId", value: productCoPurchasePrediction.ProductId),
this.CreateIntParameter("coPurchaseProductId", value: productCoPurchasePrediction.CoPurchaseProductId),
this.CreateFloatParameter("score", value: productCoPurchasePrediction.Score)),
"An error occurred while updating or creating a prediction.");
}
