public static M Sum <M>(this IAdditiveMonoid <M> g, IEnumerable <M> source)
{
var sum = g.Zero();
foreach (var value in source)
{
sum = g.Add(sum, value);
}
return(sum);
}
//For this definition one should usually assume that IAdditiveMonoid<M> is abelian
public static M ScalarMult <M>(this IAdditiveMonoid <M> g, int n, M a)
{
if (n < 0)
{
throw new ArgumentException($"n={n} < 0!");
}
var res = g.Zero();
for (var i = 0; i < n; i++)
{
res = g.Add(res, a);
}
return(res);
}