Added function that copies old state to new state

src/DomainBuffers.jl

@@ -86,6 +86,13 @@ function update_states!(dbs::DomainBuffers)
     end
 end
 
+
+function set_new_to_old_states!(dbs::DomainBuffers)
+    for db in values(dbs)
+        set_new_to_old_states!(db)
+    end
+end
+
 """
     set_time_increment!(db::Dict{String,AbstractDomainBuffer}, Δt)
     set_time_increment!(db::AbstractDomainBuffer, Δt)
@@ -181,6 +188,8 @@ get_material(b::StdDomainBuffer) = get_material(get_base(get_itembuffer(b)))
 # Update old_states = new_states after convergence 
 update_states!(b::StdDomainBuffer) = update_states!(b.states)
 
+set_new_to_old_states!(b::StdDomainBuffer) = set_new_to_old_states!(b.states)
+
 function set_time_increment!(b::StdDomainBuffer, Δt)
     set_time_increment!(get_base(get_itembuffer(b)), Δt)
 end

src/Simulation.jl

@@ -32,6 +32,7 @@ get_old_state(sim::Simulation, args::Vararg{Any, N}) where N = get_old_state(sim
 getset(sim::Simulation, args::Vararg{Any, N}) where N = getset(sim.db, args...)
 update_states!(sim::Simulation) = update_states!(sim.db)
 set_time_increment!(sim::Simulation, Δt) = set_time_increment!(sim.db, Δt)
+set_new_to_old_states!(sim::Simulation) = set_new_to_old_states!(sim.db)
 
 # Forwarding for internal API
 get_num_tasks(sim::Simulation) = get_num_tasks(sim.db)

src/states.jl

@@ -18,6 +18,12 @@ function update_states!(sv::StateVariables)
     sv.new.vals = tmp
 end
 
+function set_new_to_old_states!(sv::StateVariables)
+    for key in keys(sv.old.vals)
+        copyto!(sv.new.vals[key], sv.old.vals[key])
+    end
+end
+
 # Experimental, basically copy!, but use separate name for clarity
 function replace_states!(dst::StateVariables, src::StateVariables)
     dst.old.vals = src.old.vals