Normalized Levenshtein Distance loops forever about fuzzystring

[doublehelix]

I'm having the same issue...
According to the WIKI article (https://en.wikipedia.org/wiki/Levenshtein_distance) the implemented function is known to be a little inefficient.

There is a pseudocode example in the same article of a better implementation using a matrix.
I have implemented it and it returns in about 6ms with verified results.

public static int LevenshteinDistanceMatrix(this string source, string target)
{
    var sourceLength = source.Length;
    var targetLength = target.Length;

    var matrix = new int[sourceLength + 1, targetLength + 1];

    // First calculation, if one entry is empty return full length
    if (sourceLength == 0)
        return targetLength;

    if (targetLength == 0)
        return sourceLength;

    // Initialization of matrix with row size sourceLength and columns size targetLength
    for (var i = 0; i <= sourceLength; matrix[i, 0] = i++) { }
    for (var j = 0; j <= targetLength; matrix[0, j] = j++) { }

    // Calculate rows and collumns distances
    for (var i = 1; i <= sourceLength; i++)
    {
        for (var j = 1; j <= targetLength; j++)
        {
            var cost = (target[j - 1] == source[i - 1]) ? 0 : 1;
            matrix[i, j] = Math.Min(
                Math.Min(matrix[i - 1, j] + 1, matrix[i, j - 1] + 1),
                matrix[i - 1, j - 1] + cost);
        }
    }
    // return result
    return matrix[sourceLength, targetLength];
}

[caesay]

levenshtien algo in this lib was taking 5+ second for me on such a 15 character string. other algorithms complete this same task in milliseconds. don't use this libs levenshtien algo...