How to calculate a distance between a moving Avatar and the viewpoint?

[JohnSenior]

Dear smart Forum member,

I need to calculate the distance between the position of Avatars, moving from waypoint to waypoint, and the position of the user. At the end of each trial, the minimum distance between viewpoint of the user and avatar at any given time point of the trial should be printed out. I got this far in regard of calculating the distance towards a stable object (at 0.4, 1.8, 0; in this case):
-------------------------
# Globals
pos = []
minDist = 10000
posModel = [0.4,1.8,0]

#euklidische Distanz
def dist(posModel):
global minDist
pos = viz.MainView.getPosition()
dist = [(a - b)**2 for a, b in zip(pos, posModel)]
dist = math.sqrt(sum(dist))
if dist < minDist:
minDist = dist
print minDist
print dist

vizact.ontimer(0.1,dist, posModel)

def quit():
global minDist
print minDist
viz.quit()

vizact.onkeydown('q',quit)

------------------------
My problem: How do I get the position of Avatars, while they are moving from waypoint to waypoint? Is there a way to get the Position of moving avatars similar to "viz.MainView.getPosition()" for the Position of the user?

Best,
John