[gmx-users] dihedral angle

[Nilesh Dhumal]

Hello,

I am trying to calculate the dihedral angle between four points.

I considered two planes (ABC & BCD) and calculate the dot products of two
normals (n1 and n2)to these plane.

theta=cos-1(n1.n2)

I compared theeta values of dihedral angle with ampac and some values are
negative. I am geting all positive value.

Any one knows how to calculate sign of dihedral angle.

Thanks

Nilesh