x_m1 incorrect?

[rmcabezon]

While checking this script, I noticed that x_m1 = vx * minDt, while it should be x_m1=x - vx * minDt for an Euler backward integration. Why do we seem to keep just the displacement?

sphexa/scripts/add_m1.py

Line 51 in 73d6de6

stepHandle["x_m1"] = safely_multiply(stepHandle["vx"], minDt)