static int Sum<T>(this IEnumerable<T> arr, Func<int, T> fun)
{
    var ret = 0;
    foreach (var a in arr){
        ret += fun(a);
        yield return ret;
    }
}
public static IEnumerable<TSource> OrderBy<TSource, TKey>(
    IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
{
    var items = source.ToArray();
    var keys = items.Select(keySelector).ToArray();
    Array.Sort(keys, items);
    foreach (var item in items)
    {
        yield return item;
    }
}

var matrix = new int[10][10];
var newmatrix =
    matrix
        .OrderBy(i => i.Sum(j => j < 0 ? j : 0))
        .ToArray()