From 615ad0385f171e75256df547fddd577c0d0f6eac Mon Sep 17 00:00:00 2001
From: Lucas Aschenbach <37406743+LucasAschenbach@users.noreply.github.com>
Date: Mon, 28 Aug 2023 14:14:34 +0200
Subject: [PATCH] Set jacobian of Fun to ZeroOperator (#909)

* jacobian of Fun is ZeroOperator

* Decrease maxiterations for independent variable newton test
---
 src/Extras/autodifferentiation.jl | 2 +-
 test/ExtrasTest.jl                | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/Extras/autodifferentiation.jl b/src/Extras/autodifferentiation.jl
index 14476b6ec..a3f47c60f 100644
--- a/src/Extras/autodifferentiation.jl
+++ b/src/Extras/autodifferentiation.jl
@@ -61,7 +61,7 @@ last(d::DualFun) = DualFun(last(d.f),Evaluation(rangespace(d.J),rightendpoint)*d
 
 jacobian(d::DualFun) = d.J
 jacobian(a::Number) = zero(a)
-jacobian(f::Fun) = Operator(I,space(f))
+jacobian(f::Fun) = zero(Operator(I,space(f)))
 
 promote_rule(::Type{DF},::Type{T}) where {DF<:DualFun,T<:Number}=DualFun
 convert(::Type{DualFun},b::Number) = DualFun(b,0)
diff --git a/test/ExtrasTest.jl b/test/ExtrasTest.jl
index 858087e20..f6b7ff144 100644
--- a/test/ExtrasTest.jl
+++ b/test/ExtrasTest.jl
@@ -123,8 +123,7 @@ include(joinpath(@__DIR__, "testutils.jl"))
                 u2' - u2*u2;
             ]
 
-        # note takes a few more iterations to converge to accuracy
-        u1,u2 = newton(N_ind, [u1,u2], maxiterations=25)
+        u1,u2 = newton(N_ind, [u1,u2])
 
         u1_exact = -1 / (x - 2)
         u2_exact = -1 / (x + 2)