/// <summary> Sets the format of the input instances.
///
/// </summary>
/// <param name="instanceInfo">an Instances object containing the input instance
/// structure (any instances contained in the object are ignored - only the
/// structure is required).
/// </param>
/// <exception cref="UnsupportedAttributeTypeException">if the specified attribute
/// is neither numeric or nominal.
/// </exception>
public override bool setInputFormat(Instances instanceInfo)
{
base.setInputFormat(instanceInfo);
m_AttIndex.Upper=instanceInfo.numAttributes() - 1;
if (!Numeric && !Nominal)
{
throw new Exception("Can only handle numeric " + "or nominal attributes.");
}
m_Values.Upper=instanceInfo.attribute(m_AttIndex.Index).numValues() - 1;
if (Nominal && m_ModifyHeader)
{
instanceInfo = new Instances(instanceInfo, 0); // copy before modifying
Attribute oldAtt = instanceInfo.attribute(m_AttIndex.Index);
int[] selection = m_Values.Selection;
FastVector newVals = new FastVector();
for (int i = 0; i < selection.Length; i++)
{
newVals.addElement(oldAtt.value_Renamed(selection[i]));
}
instanceInfo.deleteAttributeAt(m_AttIndex.Index);
instanceInfo.insertAttributeAt(new Attribute(oldAtt.name(), newVals), m_AttIndex.Index);
m_NominalMapping = new int[oldAtt.numValues()];
for (int i = 0; i < m_NominalMapping.Length; i++)
{
bool found = false;
for (int j = 0; j < selection.Length; j++)
{
if (selection[j] == i)
{
m_NominalMapping[i] = j;
found = true;
break;
}
}
if (!found)
{
m_NominalMapping[i] = - 1;
}
}
}
setOutputFormat(instanceInfo);
return true;
}