[ESPResSo] Harmonic bonds

[Mikhail Stukan]

Dear all,

I have noticed that in the recent version (2.2.0b), the is a change in
the format for harmonic bond interaction. (May be the change has
happened before, I switched from 2.0.5 to 2.2.0 directly). Namely in
the conformation file I have something like

{interactions
 {1 HARMONIC 100.0 1.0 -1.0}
.....
}

My question is about the last  "-1.0". According to the manual the format is :

  inter bondid harmonic K R

so I provide

 inter 1 harmonic 100.0 1.0

But in the output configuration have this additional "-1.0" term.
Could you please tell me what is its meaning?

Thank you very much in advance,
Mikhail