public void Permutation()
{
var fact = new int[11];
fact[0] = 1;
for (int i = 1; i < fact.Length; i++)
{
fact[i] = fact[i - 1] * i;
}
var factor = new StaticModIntFactor <Mod1000000007>(10);
for (int i = 0; i <= 10; i++)
{
for (int j = 0; j <= 10; j++)
{
int expected = 1;
for (int k = 0; k < j; k++)
{
expected *= i - k;
}
factor.Permutation(i, j).Value.Should().Be(expected);
}
}
factor.Invoking(factor => factor.Permutation(11, 0)).Should().Throw <Exception>();
}
public void Homogeneous()
{
var factor = new StaticModIntFactor <Mod1000000007>(30);
for (int i = 0; i <= 10; i++)
{
for (int j = 0; j <= 20; j++)
{
factor.Homogeneous(i, j).Should().Be(factor.Combination(i + j - 1, j));
}
}
factor.Invoking(factor => factor.Homogeneous(10, 22)).Should().Throw <Exception>();
}
public void Combination()
{
var factor = new StaticModIntFactor <Mod1000000007>(10);
for (int i = 0; i <= 10; i++)
{
for (int j = 0; j <= 10; j++)
{
factor.Combination(i, j).Value.Should().Be((int)MathLibEx.Combination(i, j));
}
}
factor.Invoking(factor => factor.Combination(11, 0)).Should().Throw <Exception>();
}
public void Factorial()
{
var factor = new StaticModIntFactor <Mod1000000007>(10);
int expected = 1;
factor.Factorial(0).Value.Should().Be(1);
factor.FactorialInvers(0).Value.Should().Be(1);
for (int i = 1; i <= 10; i++)
{
expected *= i;
factor.Factorial(i).Value.Should().Be(expected);
factor.FactorialInvers(i).Should().Be(new StaticModInt <Mod1000000007>(1) / expected);
}
factor.Invoking(factor => factor.Factorial(11)).Should().Throw <Exception>();
}
