A sawtooth oscillator using the "Differentiated Parabolic Wave" technique, which suppresses aliasing at a wide range of frequencies, yet is about 3 times as CPU-efficient as SuperCollider's Saw ugen.
freq - frequency in Hertz
iphase - initial phase offset, a value ranging from -1 to 1.
It doesn't guarantee to be alias-free but sounds very good for most applications: e.g. at 44.1 kHz sample rate, aliasing can only be heard if the frequency goes over around 4 kHz. The technique is documented in Välimäki (2005) Signal Processing Letters 12(3) pages 214-217.