## Useful shell script for latest unit distance graph solver

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