protected virtual IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input, out IDataView sourceCtx, IPredictor overwritePredictor)
{
sourceCtx = input;
Contracts.CheckValue(env, "env");
env.CheckValue(args, "args");
env.CheckValue(input, "input");
IPredictor predictor;
if (overwritePredictor == null)
{
throw env.Except("No defined predictor.");
}
else
{
predictor = overwritePredictor;
}
// The function is returning something and modifying a member of the class. Not very fancy.
_predictor = predictor;
string feat = TrainUtils.MatchNameOrDefaultOrNull(env, input.Schema,
"featureColumn", args.featureColumn, DefaultColumnNames.Features);
int index = SchemaHelper.GetColumnIndex(input.Schema, feat);
var type = input.Schema[index].Type;
if (!type.IsVector() || type.AsVector().ItemType().RawKind() != DataKind.R4)
{
throw env.Except("Features must a vector of floats");
}
if (args.useProb)
{
var valueMapper = predictor as IValueMapperDist;
if (valueMapper == null)
{
throw env.Except("Predictor must be a IValueMapper.");
}
var output = valueMapper.DistType;
if (output.IsVector())
{
return(CreateTransformValueMapperDist <VBuffer <float>, VBuffer <float>, VBuffer <float> >(valueMapper, feat, args.outputColumn));
}
else
{
return(CreateTransformValueMapperDist <VBuffer <float>, VBuffer <float>, float>(valueMapper, feat, args.outputColumn));
}
}
else
{
var valueMapper = predictor as IValueMapper;
if (valueMapper == null)
{
throw env.Except("Predictor must be a IValueMapper.");
}
var output = valueMapper.OutputType;
if (output.IsVector())
{
return(CreateTransformValueMapper <VBuffer <float>, VBuffer <float> >(valueMapper, feat, args.outputColumn));
}
else
{
return(CreateTransformValueMapper <VBuffer <float>, float>(valueMapper, feat, args.outputColumn));
}
}
}
