For the unit distance graphs solver, considering only graphs that can’t be vertex-coloured with 3 colours, but that are 4-colourable, I want to know if there are any repeats in the number of 4-colourings given, which is a complete count, up to permutations of the four colors.
For this, I devised the shell script status.sh , e.g.:
$ ./status.sh
solutions found requiring four colours:
19 114 969
solutions found requiring four colours with distinct number of four-coulourings:
19 114 969
===
This tells me the solver found 19 unit distance graphs that are 4-coulourable but not 3-colourable.
Secondly, these 19 unit distance graphs all have distinct numbers of 4-colorings, or else a number less than 19 would appear after the line:
“solutions found requiring four colours with distinct number of four-coulourings:” .
The code of status.sh follows (seven lines):
#!/bin/bash
echo ‘solutions found requiring four colours:’
cat udgraph12_solverff9741g.txt | grep count_4_colorings | grep no | wc
echo ‘ ‘
echo ‘solutions found requiring four colours with distinct number of four-coulourings:’
cat udgraph12_solverff9741g.txt | grep count_4_colorings | grep no | sort -u | wc
echo ‘ ‘
P.S. The version of the solver being used is
udgraph12_solverff9741g.c from
/home/david/graphs/golomb17
$ ls -l /home/david/graphs/golomb17/udgraph12_solverff9741g.c
-rw-rw-r–. 1 david david 19977 Feb 14 15:58 /home/david/graphs/golomb17/udgraph12_solverff9741g.c
