Merge branch 'expm'

Author: ChrisRackauckas

src/array_operator.jl

@@ -52,7 +52,15 @@ Base.issymmetric(L::DiffEqArrayOperator) = L._issymmetric
 Base.ishermitian(L::DiffEqArrayOperator) = L._ishermitian
 Base.isposdef(L::DiffEqArrayOperator) = L._isposdef
 DiffEqBase.is_constant(L::DiffEqArrayOperator) = L.update_func == DEFAULT_UPDATE_FUNC
-Base.expm(L::DiffEqArrayOperator) = expm(L.α.coeff*L.A)
+function Base.expm(L::DiffEqArrayOperator)
+    tmp = full(L.A) # If not lazy then this is a no-op
+    tmp .*= L.α.coeff
+    out = expm(tmp)
+    if tmp === L.A
+        L.A ./= L.α.coeff # Undo change if not lazy
+    end
+    out
+end
 DiffEqBase.has_expm(L::DiffEqArrayOperator) = true
 Base.size(L::DiffEqArrayOperator) = size(L.A)
 DiffEqBase.update_coefficients!(L::DiffEqArrayOperator,t,u) = (L.update_func(L.A,t,u); L.α = L.α(t); nothing)