Algorithms For Dummies

Putting a Graph in Numeric Format

Precision is an important part of using algorithms. Even though too much preci-

sion hides the overall pictures from humans, computers thrive on detail. Often, 

the more detail you can provide, the better the results you receive. However, the 

form of that detail is important. To use certain algorithms, the data you provide 

must appear in certain forms or the result you receive won’t make sense (it will 

contain errors or have other issues).

Fortunately, NetworkX provides a number of functions to convert your graph into 

forms that other packages and environments can use. These functions appear at 

http://networkx.readthedocs.io/en/stable/reference/convert.html

. The 

following sections show how to present graph data as a NumPy (

http://www.

numpy.org/

) matrix, SciPy (

https://www.scipy.org/

) sparse representation, 

and a standard Python list. You use these presentations as the book progresses to 

work with the various algorithms. (The code in the following sections appears in 

the 

A4D; 08; Graph Conversion.ipynb

 file and relies on the graph you created 

in the “Counting edges and vertexes” section of the chapter.)

---

170

 

   

  PART 3