public void TestUniformity_InUnitCircle()
{
var rng = new StatelessRng(kSeed);
// Parametrization based on polar coords
Func <Vector2, Vector2?> Parametrize = cartesian => {
float radius = cartesian.magnitude;
if (radius == 0)
{
return(null);
}
// cdf = cumulative distribution function ~= "area under"
// area of cirle of radius "mag" relative to area of entire circle
// to make uniform, compute cdf(var) / cdf (total) = mag^2 / 1^2
float radiusUniform = radius * radius;
// area increases linearly with angle01, so just need to rescale to [0,1)
float angle = Mathf.Atan2(cartesian.y, cartesian.x);
float angleUniform = ToAngle01(angle);
return(new Vector2(angleUniform, radiusUniform));
};
S.CheckUniformity(new[] { "theta", "rr" },
Gen(i => Parametrize(rng.InUnitCircle(i))));
}
public void TestForSaltReuse()
{
var seen = new HashSet <int>();
var rng = new StatelessRng(kSeed);
StatelessRng.SaltUsed = (salt) => {
Assert.IsTrue(seen.Add(salt), "Salt {0} is unused", salt);
};
try {
rng.OnUnitCircle(0); seen.Clear();
rng.InUnitCircle(0); seen.Clear();
rng.OnUnitSphere(0); seen.Clear();
rng.InUnitSphere(0); seen.Clear();
rng.Rotation(0); seen.Clear();
} finally {
StatelessRng.SaltUsed = null;
}
}
public void TestCheckUniformity()
{
var rng = new StatelessRng(kSeed);
Func <Vector2, Vector2?> Parametrize = v => new Vector2((v.x + 1) / 2, (v.y + 1) / 2);
Assert.Throws <AssertionException>(() =>
S.CheckUniformity(new[] { "x", "y" },
Gen(i => Parametrize(rng.InUnitCircle(i)))));
}