/// <summary>
/// Converts the string representation of a relative semitones list into its scale definition equivalent.
/// </summary>
/// <param paramname="s">The <see cref="string"/> represention of the semitone relative distances.</param>
/// <returns>The <see cref="ScaleDefinition"/>.</returns>
/// <exception cref="System.FormatException">Throw if the format is incorrect,</exception>
public static ScaleDefinition Parse(string s)
{
var relativeSemitones = RelativeSemitoneList.Parse(s);
var result = new ScaleDefinition(relativeSemitones);
return(result);
}
public Symmetry(IReadOnlyCollection <Semitone> relativesIntervals)
{
var list = relativesIntervals.ToList();
var count = list.Count;
if (count % 2 != 0)
{
return; // Ensure count divides by 2
}
bool CheckIntervals(int candidateBlockSize)
{
if (count % candidateBlockSize != 0)
{
return(false); // Ensure count divides by blocksize
}
var blockCount = count / candidateBlockSize;
for (var i = 0; i < candidateBlockSize; i++)
{
var interval = list[i];
for (var j = 1; j < blockCount; j++)
{
var index = i + j * candidateBlockSize;
if (list[index] != interval)
{
return(false);
}
}
}
return(true);
}
var blockSize = Enumerable.Range(1, count / 2).FirstOrDefault(CheckIntervals);
if (blockSize <= 0)
{
return;
}
// Intervals are symmetric
Block = new RelativeSemitoneList(relativesIntervals.Take(blockSize));
BlockCount = count / blockSize;
}
