public DataTableNormaliser(IDataTable dataTable, NormalisationType type, Stream output = null, DataTableNormalisation model = null)
{
_table = dataTable;
_writer = new DataTableWriter(dataTable.Columns, output);
if (model != null)
{
_normalisationModel = model;
}
else
{
var analysis = dataTable.GetAnalysis();
var columnNormList = new List <DataTableNormalisation.Column>();
foreach (var columnInfo in analysis.ColumnInfo)
{
var column = dataTable.Columns[columnInfo.ColumnIndex];
if (column.IsContinuous)
{
var numericInfo = columnInfo as INumericColumnInfo;
if (numericInfo != null)
{
if (type == NormalisationType.Standard && !numericInfo.StdDev.HasValue)
{
continue;
}
DataTableNormalisation.Column columnNorm;
if (type == NormalisationType.Standard)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.StdDev.Value, numericInfo.Mean);
}
else if (type == NormalisationType.Euclidean)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.L2Norm);
}
else if (type == NormalisationType.Manhattan)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.L1Norm);
}
else if (type == NormalisationType.FeatureScale)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.Max - numericInfo.Min, numericInfo.Min);
}
else
{
throw new NotImplementedException();
}
columnNormList.Add(columnNorm);
}
}
}
_normalisationModel = new DataTableNormalisation {
Type = type,
ColumnNormalisation = columnNormList.ToArray()
};
}
}
public DataTableNormaliser(IDataTable dataTable, NormalisationType type, Stream output, IEnumerable <int> columnIndices)
{
_writer = new DataTableWriter(dataTable.Columns, output);
var analysis = dataTable.GetAnalysis();
var columnNormList = new List <DataTableNormalisation.Column>();
var columns = analysis.ColumnInfo.AsQueryable();
if (columnIndices != null)
{
var columnSet = new HashSet <int>(columnIndices);
columns = columns.Where(ci => columnSet.Contains(ci.ColumnIndex));
}
foreach (var columnInfo in columns)
{
var column = dataTable.Columns[columnInfo.ColumnIndex];
if (column.IsContinuous)
{
if (columnInfo is INumericColumnInfo numericInfo)
{
if (type == NormalisationType.Standard && !numericInfo.StdDev.HasValue)
{
continue;
}
DataTableNormalisation.Column columnNorm;
if (type == NormalisationType.Standard)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.StdDev ?? 1, numericInfo.Mean);
}
else if (type == NormalisationType.Euclidean)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.L2Norm);
}
else if (type == NormalisationType.Manhattan)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.L1Norm);
}
else if (type == NormalisationType.FeatureScale)
{
columnNorm = new DataTableNormalisation.Column(columnInfo.ColumnIndex, column.Type, numericInfo.Max - numericInfo.Min, numericInfo.Min);
}
else
{
throw new NotImplementedException();
}
columnNormList.Add(columnNorm);
}
}
}
_normalisationModel = new DataTableNormalisation {
Type = type,
ColumnNormalisation = columnNormList.ToArray()
};
}
