Example in tutorials: freezing a mode-switch variable

[MichaelClerx]

E.g. before fitting you'll want to change statements like

g_Kr = piecewise(cell.type == 0, 1, cell.type == 1, 1.2, cell.type == 2, 1.43) * g_Kr_base
  g_Kr_base = 0.123

to

g_Kr = 0.123

by doing e.g.

# Set the cell type you want
switch = m.get('cell.mode')
switch.set_rhs(1)

# Freeze all the (constant) variables to this mode
for var in switch.refs_by():
    if var.is_constant():
        # Evaluate the variable's RHS, and set its new RHS to the result
        var.set_rhs(var.eval())  # Remove the switch, if unused
        
        # Remove unused child variables, if any
        what's the best way to do this, if they depend on each other?

if not switch.refs_by():
    switch.parent().remove_variable(switch)

[MichaelClerx]

Related: Should probably add a method that lets you delete all children of a VarOwner. This can re-use the variable _delete but with has_ancestor and any ancestor instead of the more limited whole_component=True