Gurobi Python Error (NoneType has no len())
I need to write an optimization file for Gurobi (Python) that is a modified version of a classic TSP. I tried to run the example file from their website:
examples.gurobi.com/traveling-salesman-problem/
I always get the following error:
TypeError: object of type 'NoneType' has no len()
What do I need to change?
Thx
Full code: https://www.dropbox.com/s/ewisx805b3o2wq5/beispiel_opt.py?dl=0
python typeerror nonetype gurobi
asked Nov 21 '18 at 15:56
DEMDEM
11
add a comment |
I need to write an optimization file for Gurobi (Python) that is a modified version of a classic TSP. I tried to run the example file from their website:
examples.gurobi.com/traveling-salesman-problem/
I always get the following error:
TypeError: object of type 'NoneType' has no len()
What do I need to change?
Thx
Full code: https://www.dropbox.com/s/ewisx805b3o2wq5/beispiel_opt.py?dl=0
python typeerror nonetype gurobi
asked Nov 21 '18 at 15:56
DEMDEM
11
1
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40
add a comment |
I need to write an optimization file for Gurobi (Python) that is a modified version of a classic TSP. I tried to run the example file from their website:
examples.gurobi.com/traveling-salesman-problem/
I always get the following error:
TypeError: object of type 'NoneType' has no len()
What do I need to change?
Thx
Full code: https://www.dropbox.com/s/ewisx805b3o2wq5/beispiel_opt.py?dl=0
python typeerror nonetype gurobi
asked Nov 21 '18 at 15:56
DEMDEM
11
I need to write an optimization file for Gurobi (Python) that is a modified version of a classic TSP. I tried to run the example file from their website:
examples.gurobi.com/traveling-salesman-problem/
I always get the following error:
TypeError: object of type 'NoneType' has no len()
What do I need to change?
Thx
Full code: https://www.dropbox.com/s/ewisx805b3o2wq5/beispiel_opt.py?dl=0
python typeerror nonetype gurobi
python typeerror nonetype gurobi
asked Nov 21 '18 at 15:56
DEMDEM
11
asked Nov 21 '18 at 15:56
DEMDEM
11
edited Nov 21 '18 at 16:24
DEM
asked Nov 21 '18 at 15:56
DEMDEM
11
asked Nov 21 '18 at 15:56
DEMDEM
11
asked Nov 21 '18 at 15:56
DEMDEM
11
11
1
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40
add a comment |
1
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40
1
1
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40
add a comment |
1 Answer
1
active
oldest
votes
I can confirm the error with the example code from Gurobi's website. At the first look the problem seems to be inside the subtour function, that returns None if sum(lengths) == n and the missing check for if tour is None inside the subtourlim function.
Instead of providing a fix for the specific code, I first checked the examples that Gurobi installs inside the specific installation directory:
- Mac:
/Library/gurobi810/mac64/examples/python/
- Linux:
/opt/gurobi800/linux64/examples/python/
- Windows:
c:gurobi800win64examplespython
And surprisingly the tsp.py from there runs without any errors. Note also that the two mentioned functions are revised. So I guess the example from the website is just a old version of the code.
answered Nov 21 '18 at 18:23
jonijoni
778158
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
add a comment |
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I can confirm the error with the example code from Gurobi's website. At the first look the problem seems to be inside the subtour function, that returns None if sum(lengths) == n and the missing check for if tour is None inside the subtourlim function.
Instead of providing a fix for the specific code, I first checked the examples that Gurobi installs inside the specific installation directory:
- Mac:
/Library/gurobi810/mac64/examples/python/
- Linux:
/opt/gurobi800/linux64/examples/python/
- Windows:
c:gurobi800win64examplespython
And surprisingly the tsp.py from there runs without any errors. Note also that the two mentioned functions are revised. So I guess the example from the website is just a old version of the code.
answered Nov 21 '18 at 18:23
jonijoni
778158
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
add a comment |
I can confirm the error with the example code from Gurobi's website. At the first look the problem seems to be inside the subtour function, that returns None if sum(lengths) == n and the missing check for if tour is None inside the subtourlim function.
Instead of providing a fix for the specific code, I first checked the examples that Gurobi installs inside the specific installation directory:
- Mac:
/Library/gurobi810/mac64/examples/python/
- Linux:
/opt/gurobi800/linux64/examples/python/
- Windows:
c:gurobi800win64examplespython
And surprisingly the tsp.py from there runs without any errors. Note also that the two mentioned functions are revised. So I guess the example from the website is just a old version of the code.
answered Nov 21 '18 at 18:23
jonijoni
778158
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
add a comment |
I can confirm the error with the example code from Gurobi's website. At the first look the problem seems to be inside the subtour function, that returns None if sum(lengths) == n and the missing check for if tour is None inside the subtourlim function.
Instead of providing a fix for the specific code, I first checked the examples that Gurobi installs inside the specific installation directory:
- Mac:
/Library/gurobi810/mac64/examples/python/
- Linux:
/opt/gurobi800/linux64/examples/python/
- Windows:
c:gurobi800win64examplespython
And surprisingly the tsp.py from there runs without any errors. Note also that the two mentioned functions are revised. So I guess the example from the website is just a old version of the code.
answered Nov 21 '18 at 18:23
jonijoni
778158
I can confirm the error with the example code from Gurobi's website. At the first look the problem seems to be inside the subtour function, that returns None if sum(lengths) == n and the missing check for if tour is None inside the subtourlim function.
Instead of providing a fix for the specific code, I first checked the examples that Gurobi installs inside the specific installation directory:
- Mac:
/Library/gurobi810/mac64/examples/python/
- Linux:
/opt/gurobi800/linux64/examples/python/
- Windows:
c:gurobi800win64examplespython
And surprisingly the tsp.py from there runs without any errors. Note also that the two mentioned functions are revised. So I guess the example from the website is just a old version of the code.
answered Nov 21 '18 at 18:23
jonijoni
778158
answered Nov 21 '18 at 18:23
jonijoni
778158
answered Nov 21 '18 at 18:23
jonijoni
778158
answered Nov 21 '18 at 18:23
jonijoni
778158
778158
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
add a comment |
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
Thank you so much! I took the newest Version and it worked
– DEM
Nov 25 '18 at 17:40
add a comment |
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1
Can you include the code and what line you get the error on?
– All Knower
Nov 21 '18 at 16:01
Full code added. Get the error in line 16 and 82
– DEM
Nov 21 '18 at 16:25
@DEM I don't know whether it is related but line 45 at your code is not equal with the code on the website. There is an extra indent for return on your code.
– kur ag
Nov 21 '18 at 20:40