calc_ftemp_arrh         Calculates the Arrhenius-type temperature
                        response
calc_ftemp_inst_rd      Calculates the temperature response of dark
                        respiration
calc_ftemp_inst_vcmax   Calculates the instantaneous temperature
                        response of Vcmax
calc_ftemp_kphio        Calculates the temperature dependence of the
                        quantum yield efficiency
calc_gammastar          Calculates the CO2 compensation point
calc_kmm                Calculates the Michaelis Menten coefficient for
                        Rubisco-limited photosynthesis
calc_patm               Calculates atmospheric pressure
calc_soilmstress        Calculates an empirical soil moisture stress
                        factor
rpmodel                 Invokes a P-model function call
