Issues in ODE serialization with AssignmentRules on species

[matthiaskoenig]

• Units are not serialized: captot_urine = cap_urine + capss_urine # []
• no dx/dt should be generated for state variables calculated via assignment rules: d captot_urine/dt = 0 # [mmol/min]

e.g. captopril_kidney.xml

# y
CAPDISEX = f_renal_function * CAPDISEX_k * Vki * capss_ext  # [mmol/min]
CAPEX = f_renal_function * CAPEX_k * Vki * cap_ext  # [mmol/min]
captot_urine = cap_urine + capss_urine  # []

# odes
d cap_ext/dt = -CAPEX / Vext  # [mmol/l/min]
d cap_urine/dt = CAPEX  # [mmol/min]
d capss_ext/dt = -CAPDISEX / Vext  # [mmol/l/min]
d capss_urine/dt = CAPDISEX  # [mmol/min]
d captot_urine/dt = 0  # [mmol/min]