/// <summary>
/// Save a zero-row dataview that will be used to infer schema information, used in the case
/// where the tranpsose loader is instantiated with no input streams.
/// </summary>
private static void SaveSchema(IHostEnvironment env, ModelSaveContext ctx, Schema schema)
{
Contracts.AssertValue(env);
env.AssertValue(ctx);
env.AssertValue(schema);
var noRows = new EmptyDataView(env, schema);
env.Assert(noRows.GetRowCount() == 0);
var saverArgs = new BinarySaver.Arguments();
saverArgs.Silent = true;
var saver = new BinarySaver(env, saverArgs);
// We load our schema from what amounts to a binary loader, so all columns should likewise be savable.
env.Assert(Enumerable.Range(0, schema.ColumnCount).All(c => saver.IsColumnSavable(schema.GetColumnType(c))));
ctx.SaveBinaryStream("Schema.idv", w => saver.SaveData(w.BaseStream, noRows, Utils.GetIdentityPermutation(schema.ColumnCount)));
}
/// <summary>
/// Returns an appropriate generic <c>WritePipe{T}</c> for the given column.
/// </summary>
public static WritePipe Create(BinarySaver parent, RowCursor cursor, ColumnCodec col)
{
Type writePipeType = typeof(WritePipe <>).MakeGenericType(col.Codec.Type.RawType);
return((WritePipe)Activator.CreateInstance(writePipeType, parent, cursor, col));
}
protected WritePipe(BinarySaver parent)
{
Contracts.AssertValue(parent);
Parent = parent;
}