/// <summary>
/// Permute the elements of an array given a permutation.
/// </summary>
public static void Permute <T>(Narray <T> data, Narray <int> permutation)
{
if (!data.SameDims(permutation))
{
throw new Exception("CHECK_ARG: data.SameDims(permutation)");
}
Narray <bool> finished = new Narray <bool>(data.Length());
finished.Fill(false);
for (int start = 0; start < finished.Length(); start++)
{
if (finished[start])
{
continue;
}
int index = start;
T value = data[index];
for ( ; ;)
{
int next = permutation[index];
if (next == start)
{
break;
}
data[index] = data[next];
index = next;
//CHECK_ARG(!finished[index] && "not a permutation");
if (finished[index])
{
throw new Exception("CHECK_ARG: !finished[index]");
}
finished[index] = true;
index = next;
}
data[index] = value;
finished[index] = true;
}
}
public static bool SameDims <S>(Narray <T> a, Narray <S> b)
{
return(a.SameDims(b));
}
