clustertracking.motion.orientation_df

clustertracking.motion.orientation_df(f, cluster_size=2, mpp=1.0, sizes=None)

Calculate the orientation of a dataframe of clusters, given by three orthonormal unit vectors.

The input and output coordinates are given in x, y, z order. All permutations of the feature coordinates are done.

Returns positions and orientations.

Definition of coordinate systems:

For a single particle:

• random coordinate system

For the dimer (features 0 and 1):

• z axis is from center to feature 0
• xy axis are chosen randomly (with uniformly distributed angle)

For the trimer (features 0, 1, and 2):

• z axis is from center to feature 0
• x axis is perpendicular to vector from feature 0 to 1 and to z

For the tetramer (features 0, 1, 2, and 3)

• z axis is from center to feature 0
• x axis is perpendicular to vector from feature 1 to 2 and to z