/// <summary>
/// Creates a partition of positions in a collection of
/// <see cref="DoubleMatrixRow"/>
/// elements by
/// aggregating those positions occupied by a same element.
/// </summary>
/// <param name="elements">The collection of rows whose
/// positions are to be partitioned.</param>
/// <example>
/// <inheritdoc cref="IndexPartition"
/// path="para[@id='IndexPartitionEx1Intro']"/>
/// <inheritdoc cref="IndexPartition"
/// path="para[@id='IndexPartitionEx1Code']"/>
/// </example>
/// <returns>The partition of row indexes in the
/// specified collection.</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="elements"/> is <b>null</b>.
/// </exception>
public static IndexPartition <DoubleMatrixRow> Create(
DoubleMatrixRowCollection elements)
{
if (elements is null)
{
throw new ArgumentNullException(nameof(elements));
}
SortedSet <DoubleMatrixRow> distinctElements =
new();
Dictionary <DoubleMatrixRow, List <int> > indexLists =
new();
bool isNotAlreadyInElementSet;
int i = 0;
foreach (var row in elements)
{
isNotAlreadyInElementSet = distinctElements.Add(row);
if (isNotAlreadyInElementSet)
{
indexLists.Add(row, new List <int>());
}
indexLists[row].Add(i);
i++;
}
IndexPartition <DoubleMatrixRow> partition =
new();
foreach (var element in distinctElements)
{
partition[element] = new IndexCollection(
indexLists[element].ToArray(), false);
partition.partIndetifiers.Add(element);
}
return(partition);
}
/// <summary>
/// Converts
/// from <see cref="DoubleMatrixRowCollection"/> to <see cref="DoubleMatrix"/>.
/// </summary>
/// <param name="value">The object to convert.</param>
/// <returns>The converted object.</returns>
public static DoubleMatrix ToDoubleMatrix(DoubleMatrixRowCollection value)
{
return(value);
}
