From 9182a7db83e66390e850866ea7933f1ca527189c Mon Sep 17 00:00:00 2001
From: Herman Sletmoen <hermansletmoen@gmail.com>
Date: Thu, 3 Oct 2024 16:48:16 +0200
Subject: [PATCH] Restore canonical equation form 0 ~ rhs - lhs

---
 src/systems/nonlinear/nonlinearsystem.jl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/systems/nonlinear/nonlinearsystem.jl b/src/systems/nonlinear/nonlinearsystem.jl
index 3f082068e4..050eea135c 100644
--- a/src/systems/nonlinear/nonlinearsystem.jl
+++ b/src/systems/nonlinear/nonlinearsystem.jl
@@ -140,6 +140,9 @@ function NonlinearSystem(eqs, unknowns, ps;
         eqs = [eqs]
     end
 
+    # Copy equations to canonical form, but do not touch array expressions
+    eqs = [wrap(eq.lhs) isa Symbolics.Arr ? eq : 0 ~ eq.rhs - eq.lhs for eq in eqs]
+
     jac = RefValue{Any}(EMPTY_JAC)
     defaults = todict(defaults)
     defaults = Dict{Any, Any}(value(k) => value(v)