Category talk:Wren-math: Difference between revisions
→Source code: Added multinomial and binomial methods to Int class. Restricted factorial method to n < 19.
(→Source code: Added two more convenience methods to Nums class.) |
(→Source code: Added multinomial and binomial methods to Int class. Restricted factorial method to n < 19.) |
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Line 164:
}
// Returns the factorial of 'n'
static factorial(n) {
if (!(n is Num && n >= 0
Fiber.abort("Argument must be a non-negative integer < 19.")
}
if (n < 2) return 1
var fact = 1
Line 172 ⟶ 174:
return fact
}
// Returns the multinomial coefficient of n over a list f where sum(f) == n.
static multinomial(n, f) {
if (!(n is Num && n >= 0 && n < 19)) {
Fiber.abort("First argument must be a non-negative integer < 19.")
}
if (!(f is List)) Fiber.abort("Second argument must be a list.")
var sum = f.reduce { |acc, i| acc + i }
if (n != sum) {
Fiber.abort("The elements of the list must sum to 'n'.")
}
var prod = 1
for (e in f) {
if (e < 0) Fiber.abort("The elements of the list must be non-negative integers.")
if (e > 1) prod = prod * factorial(e)
}
return factorial(n)/prod
}
// Returns the binomial coefficent of n over k.
static binomial(n, k) { multinomial(n, [k, n-k]) }
// Determines whether 'n' is prime using a wheel with basis [2, 3].
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