117 static_cast<const specie&>(pg1)
118 + static_cast<const specie&>(pg2)
123 inline perfectGas
operator-
131 static_cast<const specie&>(pg1)
132 - static_cast<const specie&>(pg2)
137 inline perfectGas
operator*
143 return perfectGas(s*static_cast<const specie&>(pg));
147 inline perfectGas
operator==