arrays - How to get all possible paths through a graph of knots easily in php -

i want calculate costs each possible path through network (geographical). therefore need every possible combination of knots in network.

we have simple case: knots 1-4 fixed startpoint @ 1 , condition every knot has part of path -> length every path equal

1->2->3->4  1->2->4->3  1->3->2->4  1->3->4->2  1->4->2->3  1->4->3->2 

my preferred result should be:

<?php  $array = array( array(1,2,3,4), array(1,2,4,3), array(1,3,2,4), array(1,3,4,2), array(1,4,2,3), array(1,4,3,2) ) ?> 

can tell me how calculate possible paths through network given number of knots , fixed start?

thanks in advance!