From 5fe89c0f9ff2919f05e3ef2147e6c3cd8a325b7e Mon Sep 17 00:00:00 2001
From: Kevin Constantineau <146906008+BaronNashville@users.noreply.github.com>
Date: Thu, 12 Mar 2026 10:02:01 -0400
Subject: [PATCH] Improved matrix exponential for real matrices

---
 ext/IntervalArithmeticLinearAlgebraExt.jl | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/ext/IntervalArithmeticLinearAlgebraExt.jl b/ext/IntervalArithmeticLinearAlgebraExt.jl
index 32a7d25a..954bc5c9 100644
--- a/ext/IntervalArithmeticLinearAlgebraExt.jl
+++ b/ext/IntervalArithmeticLinearAlgebraExt.jl
@@ -203,11 +203,15 @@ end
 
 # matrix exponential and logarithm
 
-function LinearAlgebra.exp!(A::AbstractMatrix{<:RealOrComplexI})
+function LinearAlgebra.exp!(A::AbstractMatrix{T}) where T<:RealOrComplexI
     # note: this function does not overwrite `A`
     Λ, V = LinearAlgebra.eigen(A)
     V⁻¹ = inv(V)
-    return V * LinearAlgebra.Diagonal(exp.(Λ)) * V⁻¹
+    if T <: Real
+        return real(V * LinearAlgebra.Diagonal(exp.(Λ)) * V⁻¹)
+    else
+        return V * LinearAlgebra.Diagonal(exp.(Λ)) * V⁻¹
+    end
 end
 
 function LinearAlgebra.log(A::AbstractMatrix{<:Interval})