public void TestInv()
{
for (int i = 0; i < 5; i++)
{
var a = Random();
var b = SL2.Inv(a);
var c = a * b;
Assert.AreEqual(SL2.ID, c);
}
}
private SL2 Random()
{
var r = new SL2();
r[0][0] = GF127.Random();
r[0][1] = GF127.Random();
r[1][0] = GF127.Random();
// d = a^-1 * (1 + b*c)
r[1][1] = GF127.Inv(r[0][0]) * (r[0][1] * r[1][0] + new GF127(1, 0));
return(r);
}