Fix isdelay for NonlinearSystem

SciML · Jul 11, 2023 · d76d73f · d76d73f
1 parent 045782f
commit d76d73f
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/src/systems/diffeqs/abstractodesystem.jl b/src/systems/diffeqs/abstractodesystem.jl
@@ -159,6 +159,7 @@ function generate_function(sys::AbstractODESystem, dvs = states(sys), ps = param
 end
 
 function isdelay(var, iv)
+ iv === nothing && return false
  isvariable(var) || return false
  if istree(var) && !ModelingToolkit.isoperator(var, Symbolics.Operator)
  args = arguments(var)