[gmx-users] Negative w problem

[Hua Wong]

During a CG minimisation, I obtain the error :

Negative w:  -2.046612587870e+15
z=  -2.548360507670e+07
gpa=   1.347161368257e+07, gpb=   2.001264866334e+08
a=   0.000000000000e+00, b=   2.602946975128e-08
EpotA=  -1.441275875024e+04, EpotB=  -1.441068436024e+04
Negative number for sqrt encountered (-2046612587870065.500000)
Terminating minimization

I read the mailing list about problems like this, and found something about double precision. But I do use double precision gromacs.

Any hint about the negative w ? It is the first time I encounter it.

What are the possible problems?

Thanks