Reading in TSP file Python

Question

I need to figure out how to read in this data of the filename 'berlin52.tsp'

This is the format I'm using

NAME: berlin52
TYPE: TSP
COMMENT: 52 locations in Berlin (Groetschel)
DIMENSION : 52
EDGE_WEIGHT_TYPE : EUC_2D
NODE_COORD_SECTION
1 565.0 575.0
2 25.0 185.0
3 345.0 750.0
4 945.0 685.0
5 845.0 655.0
6 880.0 660.0
7 25.0 230.0
8 525.0 1000.0
9 580.0 1175.0
10 650.0 1130.0

And this is my current code

# Open input file
infile = open('berlin52.tsp', 'r')

# Read instance header
Name = infile.readline().strip().split()[1] # NAME
FileType = infile.readline().strip().split()[1] # TYPE
Comment = infile.readline().strip().split()[1] # COMMENT
Dimension = infile.readline().strip().split()[1] # DIMENSION
EdgeWeightType = infile.readline().strip().split()[1] # EDGE_WEIGHT_TYPE
infile.readline()

# Read node list
nodelist = []
N = int(intDimension)
for i in range(0, int(intDimension)):
    x,y = infile.readline().strip().split()[1:]
    nodelist.append([int(x), int(y)])

# Close input file
infile.close()

The code should read in the file, output out a list of tours with the values "1, 2, 3..." and more while the x and y values are stored to be calculated for distances. It can collect the headers, at least. The problem arises when creating a list of nodes.

This is the error I get though

ValueError: invalid literal for int() with base 10: '565.0'

What am I doing wrong here?

Answer 1

This is a file in TSPLIB format. To load it in python, take a look at the python package tsplib95, available through PyPi or on Github

Documentation is available on https://tsplib95.readthedocs.io/

You can convert the TSPLIB file to a networkx graph and retrieve the necessary information from there.