/// <summary>
/// Looks for a predictor among tagged predictors.
/// If the tag ends by .zip, it assumes it is a file.
/// </summary>
/// <param name="env">environment</param>
/// <param name="input">IDataView</param>
/// <param name="tag">tag name</param>
/// <returns>predictor</returns>
public static IPredictor GetTaggedPredictor(IHostEnvironment env, IDataView input, string tag)
{
if (string.IsNullOrEmpty(tag))
{
throw env.Except("tag must not be null.");
}
if (tag.EndsWith(".zip"))
{
using (Stream modelStream = new FileStream(tag, FileMode.Open, FileAccess.Read))
{
var ipred = ComponentCreation.LoadPredictorOrNull(env, modelStream);
return(ipred);
}
}
else
{
var tagged = TagHelper.EnumerateTaggedView(true, input).Where(c => c.Item1 == tag);
if (!tagged.Any())
{
throw env.Except("Unable to find any view with tag '{0}'.", tag);
}
if (tagged.Skip(1).Any())
{
var allTagged = TagHelper.EnumerateTaggedView(true, input).ToArray();
throw env.Except("Ambiguous tag '{0}' - {1}/{2}.", tag,
allTagged.Where(c => c.Item1 == tag).Count(), allTagged.Length);
}
var predictor = tagged.First().Item2.TaggedPredictor;
if (predictor == null)
{
env.Except("Tagged view '{0}' does not host a predictor.", tag);
}
return(predictor);
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="env">environment</param>
/// <param name="modelStream">stream</param>
/// <param name="output">name of the output column</param>
/// <param name="outputIsFloat">output is a gloat (true) or a vector of floats (false)</param>
/// <param name="conc">number of concurrency threads</param>
/// <param name="features">features name</param>
public ValueMapperPredictionEngineFloat(IHostEnvironment env, Stream modelStream,
string output = "Probability", bool outputIsFloat = true, int conc = 1,
string features = "Features")
{
_env = env;
if (_env == null)
{
throw Contracts.Except("env must not be null");
}
var inputs = new FloatVectorInput[0];
var view = ComponentCreation.CreateStreamingDataView <FloatVectorInput>(_env, inputs);
long modelPosition = modelStream.Position;
_predictor = ComponentCreation.LoadPredictorOrNull(_env, modelStream);
if (_predictor == null)
{
throw _env.Except("Unable to load a model.");
}
modelStream.Seek(modelPosition, SeekOrigin.Begin);
_transforms = ComponentCreation.LoadTransforms(_env, modelStream, view);
if (_transforms == null)
{
throw _env.Except("Unable to load a model.");
}
var data = _env.CreateExamples(_transforms, features);
if (data == null)
{
throw _env.Except("Cannot create rows.");
}
var scorer = _env.CreateDefaultScorer(data, _predictor);
if (scorer == null)
{
throw _env.Except("Cannot create a scorer.");
}
_valueMapper = new ValueMapperFromTransformFloat <VBuffer <float> >(_env,
scorer, features, output, conc: conc);
if (_valueMapper == null)
{
throw _env.Except("Cannot create a mapper.");
}
if (outputIsFloat)
{
_mapper = _valueMapper.GetMapper <VBuffer <float>, float>();
_mapperVector = null;
}
else
{
_mapper = null;
_mapperVector = _valueMapper.GetMapper <VBuffer <float>, VBuffer <float> >();
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="env">environment</param>
/// <param name="modelStream">stream</param>
/// <param name="conc">number of concurrency threads</param>
/// <param name="features">features column</param>
public ValueMapperPredictionEngine(IHostEnvironment env, Stream modelStream,
int conc = 1, string features = "Features")
{
_env = env;
if (_env == null)
{
throw Contracts.Except("env must not be null");
}
var inputs = new TRowValue[0];
var view = ComponentCreation.CreateStreamingDataView <TRowValue>(_env, inputs);
long modelPosition = modelStream.Position;
_predictor = ComponentCreation.LoadPredictorOrNull(_env, modelStream);
if (_predictor == null)
{
throw _env.Except("Unable to load a model.");
}
modelStream.Seek(modelPosition, SeekOrigin.Begin);
_transforms = ComponentCreation.LoadTransforms(_env, modelStream, view);
if (_transforms == null)
{
throw _env.Except("Unable to load a model.");
}
var data = _env.CreateExamples(_transforms, features);
if (data == null)
{
throw _env.Except("Cannot create rows.");
}
var scorer = _env.CreateDefaultScorer(data, _predictor);
if (scorer == null)
{
throw _env.Except("Cannot create a scorer.");
}
_CreateMapper(scorer, conc);
}
