Module malachite_base::num::arithmetic::factorial
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Traits for computing the factorial, double factorial, multifactorial, and subfactorial. Each
function has a trait whose implementations panic if the result cannot be represented, and a
checked trait whose implementations return None in that case. The traits are
Factorial, DoubleFactorial,
Multifactorial, Subfactorial,
CheckedFactorial,
CheckedDoubleFactorial,
CheckedMultifactorial, and
CheckedSubfactorial.
factorial
use malachite_base::num::arithmetic::traits::Factorial;
assert_eq!(u8::factorial(0), 1);
assert_eq!(u8::factorial(1), 1);
assert_eq!(u8::factorial(2), 2);
assert_eq!(u8::factorial(3), 6);
assert_eq!(u8::factorial(4), 24);
assert_eq!(u8::factorial(5), 120);
assert_eq!(u32::factorial(10), 3628800);checked_factorial
use malachite_base::num::arithmetic::traits::CheckedFactorial;
assert_eq!(u8::checked_factorial(0), Some(1));
assert_eq!(u8::checked_factorial(1), Some(1));
assert_eq!(u8::checked_factorial(2), Some(2));
assert_eq!(u8::checked_factorial(3), Some(6));
assert_eq!(u8::checked_factorial(4), Some(24));
assert_eq!(u8::checked_factorial(5), Some(120));
assert_eq!(u8::checked_factorial(6), None);
assert_eq!(u32::checked_factorial(10), Some(3628800));
assert_eq!(u32::checked_factorial(100), None);double_factorial
use malachite_base::num::arithmetic::traits::DoubleFactorial;
assert_eq!(u8::double_factorial(0), 1);
assert_eq!(u8::double_factorial(1), 1);
assert_eq!(u8::double_factorial(2), 2);
assert_eq!(u8::double_factorial(3), 3);
assert_eq!(u8::double_factorial(4), 8);
assert_eq!(u8::double_factorial(5), 15);
assert_eq!(u8::double_factorial(6), 48);
assert_eq!(u8::double_factorial(7), 105);
assert_eq!(u32::double_factorial(19), 654729075);
assert_eq!(u32::double_factorial(20), 3715891200);checked_double_factorial
use malachite_base::num::arithmetic::traits::CheckedDoubleFactorial;
assert_eq!(u8::checked_double_factorial(0), Some(1));
assert_eq!(u8::checked_double_factorial(1), Some(1));
assert_eq!(u8::checked_double_factorial(2), Some(2));
assert_eq!(u8::checked_double_factorial(3), Some(3));
assert_eq!(u8::checked_double_factorial(4), Some(8));
assert_eq!(u8::checked_double_factorial(5), Some(15));
assert_eq!(u8::checked_double_factorial(6), Some(48));
assert_eq!(u8::checked_double_factorial(7), Some(105));
assert_eq!(u8::checked_double_factorial(8), None);
assert_eq!(u32::checked_double_factorial(19), Some(654729075));
assert_eq!(u32::checked_double_factorial(20), Some(3715891200));
assert_eq!(u32::checked_double_factorial(100), None);multifactorial
use malachite_base::num::arithmetic::traits::Multifactorial;
assert_eq!(u8::multifactorial(0, 1), 1);
assert_eq!(u8::multifactorial(1, 1), 1);
assert_eq!(u8::multifactorial(2, 1), 2);
assert_eq!(u8::multifactorial(3, 1), 6);
assert_eq!(u8::multifactorial(4, 1), 24);
assert_eq!(u8::multifactorial(5, 1), 120);
assert_eq!(u8::multifactorial(0, 2), 1);
assert_eq!(u8::multifactorial(1, 2), 1);
assert_eq!(u8::multifactorial(2, 2), 2);
assert_eq!(u8::multifactorial(3, 2), 3);
assert_eq!(u8::multifactorial(4, 2), 8);
assert_eq!(u8::multifactorial(5, 2), 15);
assert_eq!(u8::multifactorial(6, 2), 48);
assert_eq!(u8::multifactorial(7, 2), 105);
assert_eq!(u8::multifactorial(0, 3), 1);
assert_eq!(u8::multifactorial(1, 3), 1);
assert_eq!(u8::multifactorial(2, 3), 2);
assert_eq!(u8::multifactorial(3, 3), 3);
assert_eq!(u8::multifactorial(4, 3), 4);
assert_eq!(u8::multifactorial(5, 3), 10);
assert_eq!(u8::multifactorial(6, 3), 18);
assert_eq!(u8::multifactorial(7, 3), 28);
assert_eq!(u8::multifactorial(8, 3), 80);
assert_eq!(u8::multifactorial(9, 3), 162);
assert_eq!(u32::multifactorial(10, 1), 3628800);
assert_eq!(u32::multifactorial(20, 2), 3715891200);
assert_eq!(u32::multifactorial(25, 3), 608608000);checked_multifactorial
use malachite_base::num::arithmetic::traits::CheckedMultifactorial;
assert_eq!(u8::checked_multifactorial(0, 1), Some(1));
assert_eq!(u8::checked_multifactorial(1, 1), Some(1));
assert_eq!(u8::checked_multifactorial(2, 1), Some(2));
assert_eq!(u8::checked_multifactorial(3, 1), Some(6));
assert_eq!(u8::checked_multifactorial(4, 1), Some(24));
assert_eq!(u8::checked_multifactorial(5, 1), Some(120));
assert_eq!(u8::checked_multifactorial(6, 1), None);
assert_eq!(u8::checked_multifactorial(0, 2), Some(1));
assert_eq!(u8::checked_multifactorial(1, 2), Some(1));
assert_eq!(u8::checked_multifactorial(2, 2), Some(2));
assert_eq!(u8::checked_multifactorial(3, 2), Some(3));
assert_eq!(u8::checked_multifactorial(4, 2), Some(8));
assert_eq!(u8::checked_multifactorial(5, 2), Some(15));
assert_eq!(u8::checked_multifactorial(6, 2), Some(48));
assert_eq!(u8::checked_multifactorial(7, 2), Some(105));
assert_eq!(u8::checked_multifactorial(8, 2), None);
assert_eq!(u8::checked_multifactorial(0, 3), Some(1));
assert_eq!(u8::checked_multifactorial(1, 3), Some(1));
assert_eq!(u8::checked_multifactorial(2, 3), Some(2));
assert_eq!(u8::checked_multifactorial(3, 3), Some(3));
assert_eq!(u8::checked_multifactorial(4, 3), Some(4));
assert_eq!(u8::checked_multifactorial(5, 3), Some(10));
assert_eq!(u8::checked_multifactorial(6, 3), Some(18));
assert_eq!(u8::checked_multifactorial(7, 3), Some(28));
assert_eq!(u8::checked_multifactorial(8, 3), Some(80));
assert_eq!(u8::checked_multifactorial(9, 3), Some(162));
assert_eq!(u8::checked_multifactorial(10, 3), None);
assert_eq!(u32::checked_multifactorial(10, 1), Some(3628800));
assert_eq!(u32::checked_multifactorial(20, 2), Some(3715891200));
assert_eq!(u32::checked_multifactorial(25, 3), Some(608608000));
assert_eq!(u32::checked_multifactorial(100, 1), None);
assert_eq!(u32::checked_multifactorial(100, 2), None);
assert_eq!(u32::checked_multifactorial(100, 3), None);subfactorial
use malachite_base::num::arithmetic::traits::Subfactorial;
assert_eq!(u8::subfactorial(0), 1);
assert_eq!(u8::subfactorial(1), 0);
assert_eq!(u8::subfactorial(2), 1);
assert_eq!(u8::subfactorial(3), 2);
assert_eq!(u8::subfactorial(4), 9);
assert_eq!(u8::subfactorial(5), 44);
assert_eq!(u32::subfactorial(10), 1334961);checked_subfactorial
use malachite_base::num::arithmetic::traits::CheckedSubfactorial;
assert_eq!(u8::checked_subfactorial(0), Some(1));
assert_eq!(u8::checked_subfactorial(1), Some(0));
assert_eq!(u8::checked_subfactorial(2), Some(1));
assert_eq!(u8::checked_subfactorial(3), Some(2));
assert_eq!(u8::checked_subfactorial(4), Some(9));
assert_eq!(u8::checked_subfactorial(5), Some(44));
assert_eq!(u8::checked_subfactorial(6), None);
assert_eq!(u32::checked_subfactorial(10), Some(1334961));
assert_eq!(u32::checked_subfactorial(100), None);