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fix ellipk and ellipe #499

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fix ellipk and ellipe #499

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d542b61
fix ellipk and ellipe
ogauthe Jul 9, 2025
2575b8b
use ===
ogauthe Jul 10, 2025
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10 changes: 8 additions & 2 deletions src/ellip.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,9 @@ As suggested in this paper, the domain is restricted to ``(-\infty,1]``.
ellipk(m::Real) = _ellipk(float(m))

function _ellipk(m::Float64)
isnan(m) && return NaN
(m === -Inf) && return 0.0

flag_is_m_neg = false
if m < 0.0
x = m / (m-1) #dealing with negative args
Expand All @@ -49,7 +52,7 @@ function _ellipk(m::Float64)
return Float64(halfπ)

elseif x == 1.0
return Inf
return flag_is_m_neg ? 0.0 : Inf

elseif x > 1.0
throw(DomainError(m, "`m` must lie between -Inf and 1 ---- Domain: (-Inf,1.0]"))
Expand Down Expand Up @@ -207,6 +210,9 @@ As suggested in this paper, the domain is restricted to ``(-\infty,1]``.
ellipe(m::Real) = _ellipe(float(m))

function _ellipe(m::Float64)
isnan(m) && return NaN
(m === -Inf) && return Inf

flag_is_m_neg = false
if m < 0.0
x = m / (m-1) #dealing with negative args
Expand All @@ -219,7 +225,7 @@ function _ellipe(m::Float64)
if x == 0.0
return Float64(halfπ)
elseif x == 1.0
return 1.0
return flag_is_m_neg ? Inf : 1.0

elseif x > 1.0
throw(DomainError(m,"`m` must lie between -Inf and 1 ---- Domain : (-inf,1.0]"))
Expand Down
6 changes: 6 additions & 0 deletions test/ellip.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,9 @@
@test ellipk(1.0) == Inf
@test ellipk(Float16(0.92)) ≈ 2.683551406315229344 rtol=2*eps(Float16)
@test ellipk(Float32(0.92)) ≈ 2.683551406315229344 rtol=2*eps(Float32)
@test isnan(ellipk(NaN))
@test ellipk(-Inf) == 0.0
@test ellipk(-1e30) ≈ 0.0 atol=1e-13
@test_throws MethodError ellipk(BigFloat(0.5))
@test_throws DomainError ellipk(1.1)
end
Expand All @@ -38,6 +41,9 @@
@test ellipe(1.0) ≈ 1.00 rtol=2*eps()
@test ellipe(Float16(0.865)) ≈ 1.1322436887003925 rtol=2*eps(Float16)
@test ellipe(Float32(0.865)) ≈ 1.1322436887003925 rtol=2*eps(Float32)
@test isnan(ellipe(NaN))
@test ellipe(-Inf) == Inf
@test ellipe(-1e16) > ellipe(-1e15)
@test_throws MethodError ellipe(BigFloat(-1))
@test_throws DomainError ellipe(1.2)
end
Expand Down
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