Wed Oct  8 07:47:23 2025

floyd_test():
  python version: 3.10.12
  numpy version:  1.26.4
  Test floyd().

floyd_test01():
  floyd() uses Floyds algorithm to find the
  shortest distance between all pairs of nodes
  in a directed graph, starting from the initial array
  of direct node-to-node distances.

  Node-to-node one-step distance array A:
[[ 0.  2.  5. inf inf inf]
 [inf  0.  7.  1. inf  8.]
 [inf inf  0.  4. inf inf]
 [inf inf inf  0.  3. inf]
 [inf inf  2. inf  0.  3.]
 [inf  5. inf  2.  4.  0.]]
  Node-to-node shortest total distance array B:
[[ 0.  2.  5.  3.  6.  9.]
 [inf  0.  6.  1.  4.  7.]
 [inf 15.  0.  4.  7. 10.]
 [inf 11.  5.  0.  3.  6.]
 [inf  8.  2.  5.  0.  3.]
 [inf  5.  6.  2.  4.  0.]]

floyd_test02():
  Test floyd() on matrices of increasing order N.
  The work is roughly N^3.

         N   Time (seconds)  Time/N^3

         1      0.000007      6.675720
         2      0.000016      1.966953
         4      0.000090      1.400709
         8      0.000632      1.233537
        16      0.004964      1.211942
        32      0.039384      1.201901
        64      0.144199      0.550076
       128      1.126206      0.537017
       256      9.044621      0.539101

floyd_test03()
  floyd() starts with the adjacency matrix A of a
  triangulation, determines the pairwise distance matrix B.
  One-step distance matrix:
[[ 0.  1. inf ... inf inf inf]
 [ 1.  0.  1. ... inf inf inf]
 [inf  1.  0. ... inf inf inf]
 ...
 [inf inf inf ...  0.  1. inf]
 [inf inf inf ...  1.  0.  1.]
 [inf inf inf ... inf  1.  0.]]
  Floyd distance matrix:
[[ 0.          1.          2.         ... 13.41421356 13.
  14.        ]
 [ 1.          0.          1.         ... 12.41421356 12.
  13.        ]
 [ 2.          1.          0.         ... 11.41421356 11.
  12.        ]
 ...
 [13.41421356 12.41421356 11.41421356 ...  0.          1.
   2.        ]
 [13.         12.         11.         ...  1.          0.
   1.        ]
 [14.         13.         12.         ...  2.          1.
   0.        ]]
  Graphics saved as "floyd_test03.png"

floyd_test():
  Normal end of execution.
Wed Oct  8 07:47:34 2025