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Allow calling stirlings1 and stirlings2 with Integer arguments #193

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Merged
inkydragon merged 2 commits into from
Jun 1, 2025
Merged

Allow calling stirlings1 and stirlings2 with Integer arguments #193

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11fd77b
Allow calling `stirlings1` and `stirlings2` with `Integer` arguments
FedericoStra May 11, 2025
f04d493
Add tests for `stirlings1` and `stirlings2` with large arguments
FedericoStra May 11, 2025
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11 changes: 8 additions & 3 deletions src/numbers.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -125,7 +125,12 @@ function lucasnum(n::Integer)
return z[]
end

function stirlings1(n::Int, k::Int, signed::Bool=false)
"""
stirlings1(n::Integer, k::Integer)

Compute the Stirling number of the first kind, `s(n,k)`.
"""
function stirlings1(n::Integer, k::Integer, signed::Bool=false)
if signed == true
return (-1)^(n - k) * stirlings1(n, k)
end
Expand All @@ -152,11 +157,11 @@ function stirlings1(n::Int, k::Int, signed::Bool=false)
end

"""
stirlings2(n::Int, k::Int)
stirlings2(n::Integer, k::Integer)

Compute the Stirling number of the second kind, `S(n,k)`.
"""
function stirlings2(n::Int, k::Int)
function stirlings2(n::Integer, k::Integer)
if n < 0
throw(DomainError(n, "n must be nonnegative"))
elseif n == k == 0
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2 changes: 2 additions & 0 deletions test/numbers.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@
@test stirlings1(6, 6) == 1
@test stirlings1(6, 6, true) == 1
@test sum([abs(stirlings1(8, i, true)) for i = 0:8]) == factorial(8)
@test stirlings1(big"26", 10) == 196928100451110820242880

# stirlings2
@test_throws DomainError stirlings2(-1, 1)
Expand All @@ -65,6 +66,7 @@
@test stirlings2(6, 4) == 65
@test stirlings2(6, 5) == 15
@test stirlings2(6, 6) == 1
@test stirlings2(big"26", 10) == 13199555372846848005

# bell
@test bellnum.(0:10) == [
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