/// <summary>
/// Work out if this leaf node should split. If it should, a new split value and dimension is calculated
/// based on the dimension with the largest range.
/// </summary>
/// <returns>True if the node split, false if not.</returns>
private bool CalculateSplit()
{
// Don't split if we are just one point.
if (bSinglePoint)
{
return(false);
}
// Find the dimension with the largest range. This will be our split dimension.
DomainType fWidth = d_algebra.AddIdentity;
for (int i = 0; i < d_dimension_count; i++)
{
DomainType fDelta = d_algebra.Subtract(tMaxBound[i], tMinBound[i]);
if (d_algebra.IsNaN(fDelta))
{
fDelta = d_algebra.AddIdentity;
}
if (fDelta.CompareTo(fWidth) == 1)
{
d_split_dimension = i;
fWidth = fDelta;
}
}
// If we are not wide (i.e. all the points are in one place), don't split.
if (fWidth.Equals(d_algebra.AddIdentity))
{
return(false);
}
// Split in the middle of the node along the widest dimension.
d_split_value = d_algebra.Mean(tMinBound[d_split_dimension], tMaxBound[d_split_dimension]);
// Never split on infinity or NaN.
if (d_split_value.Equals(d_algebra.PositiveInfinity))
{
d_split_value = d_algebra.MaxValue;
}
else if (d_split_value.Equals(d_algebra.NegativeInfinity))
{
d_split_value = d_algebra.MinValue;
}
// Don't let the split value be the same as the upper value as
// can happen due to rounding errors!
if (d_split_value.Equals(tMaxBound[d_split_dimension]))
{
d_split_value = tMinBound[d_split_dimension];
}
// Success
return(true);
}