Apply dynamical function to each point in phase space (represented by a 2D matrix)

Question

I have a matrix of integers, phase_space of shape (n,n), where each entry represents the number of points in that location in space. I also have tw

Answer 1

You can use pandas.DataFrame.groupby() to accumulate all moves with same coordinates in phase_space:

new_phase_space + (pd.DataFrame(phase_space)
           .stack()
           .groupby([u_x.ravel(), u_y.ravel()])
           .sum()
           .unstack(fill_value=0)
           .values
)

Output:

array([[2., 2., 4.],
       [2., 0., 4.],
       [0., 4., 0.]])