import numpy as np
from decimal import Decimal

from ..units import HighPrecisionMatrix

def calculate_distances(positions):
    N = len(positions)
    dists = HighPrecisionMatrix(N,N)
    for i in range(N):
        dists[i][i] = Decimal(0)
        for j in range(i+1, N):
            d = sum([x**2 for x in (positions[i]-positions[j])]).sqrt()
            dists[i][j] = Decimal(d)
            dists[j][i] = Decimal(d)
    return dists