private BindingsImpl(DataViewSchema input, ISchemaBoundRowMapper mapper, string suffix, string scoreColumnKind,
bool user, int scoreColIndex, DataViewType predColType)
: base(input, mapper, suffix, user, DefaultColumnNames.PredictedLabel)
{
Contracts.AssertNonEmpty(scoreColumnKind);
Contracts.Assert(DerivedColumnCount == 1);
ScoreColumnIndex = scoreColIndex;
ScoreColumnKind = scoreColumnKind;
PredColType = predColType;
_getScoreColumnKind = GetScoreColumnKind;
_getScoreValueKind = GetScoreValueKind;
// REVIEW: This logic is very specific to multiclass, which is deeply
// regrettable, but the class structure as designed and the status of this schema
// bearing object makes pushing the logic into the multiclass scorer almost impossible.
if (predColType is KeyType predColKeyType && predColKeyType.Count > 0)
{
var scoreColMetadata = mapper.OutputSchema[scoreColIndex].Metadata;
var slotColumn = scoreColMetadata.Schema.GetColumnOrNull(MetadataUtils.Kinds.SlotNames);
if (slotColumn?.Type is VectorType slotColVecType && (ulong)slotColVecType.Size == predColKeyType.Count)
{
Contracts.Assert(slotColVecType.Size > 0);
_predColMetadata = Utils.MarshalInvoke(KeyValueMetadataFromMetadata <int>, slotColVecType.RawType,
scoreColMetadata, slotColumn.Value);
}
internal static DataViewRow MetadataAsRow(DataViewSchema.Metadata metadata)
{
Contracts.CheckValue(metadata, nameof(metadata));
return(new MetadataRow(metadata));
}
public MetadataRow(DataViewSchema.Metadata metadata)
{
Contracts.AssertValue(metadata);
_metadata = metadata;
}