indicates the position of the spatial data attribute.
mat
a matrix indicating distances
pre_order
predefined order
snd
indicates which node will be used as the starting one. The default value 0 means
that the best route will be chosen, without taking into consideration which the starting
node will be.
zzz
a route
instz
instance
cost
cost of routes
Value
return a list of 3 objects: a) The modified dataset, b) winner route, c) the
total distance of the route.