Both CBwaves and the code of the Columbia group developed by Janna Levin use the PN equations to describe the evolution and the emitted waveforms of binary systems. The main differences in the applied approximation can be summarized as:
The
Domain of validity
The
The radiation reaction terms at 2.5PN and 3.5PN depends on 2 and 6 parameters, see e.g. IyerWill95. These arbitrary parameters represent the residual gauge freedom in the relative coordinate x=x1-x2 leaving the formulas for energy and angular momentum flux invariant. CBwaves and the code of the Columbia group use different gauges BT and DD. The DD gauge can be easily analyzed within CBwaves. With the appropriate coordinate transformation (applied at 2.5PN order in the figure below) we can change form one system to the other.