### BDF1 not converging

Has anyone been able to converge their BDF of order 1? This is the first integration at the first time step, which will be used to seed the order 2 BDF eventually.

My correction term (deltaZ) has a few values in it that just wont converge to zero. They just start to oscillate around ± 0.03.

My initial conditions seem correct (at least they match what I computed during inv dynamics analysis).

If you've figured this out, I'd like to compare system values (psi, g, phi, F, tauHat, etc.) to see where things are going wrong. Email me.

Samuel

saacuna@wisc.edu