Is this a doubled voltage rectifier circuit?

This is a double-voltage rectifier circuit. When Ui is negative half-cycle, VD1 conducts, charging C1, (left negative right positive); Ui is positive half-cycle, VD2 conducts, the input of VD2 is the voltage of Ui in series with C1, and the voltage on R1 is 2 times the voltage DC. there is no need for capacitor at R1.