public function testPowerSet()
{
require "app/state.php";
//initialize test input
$input = array("A", "B");
//get the power set
$result = powerSet($input);
//Make sure the outputs are correct
$this->assertContains(array(), $result);
$this->assertContains(array("A"), $result);
$this->assertContains(array("B"), $result);
$this->assertContains(array("A", "B"), $result);
}
/**
* Main logic of the server, performs the NFA to DFA conversion via subset transformation
* @param array $stateNames array of NFA state names for easy access
* @param array $transitions array of transitions for easy access
* @param array $nfaStates array of States of an NFA generated by jsonToStateArray function
* @return array array of States of a DFA, state names will be stringified
*/
function transformToDfa($stateNames, $transitions, $nfaStates)
{
$dfaStates = [];
// generate an array of blank DFAStates based on the power set of the NFA States
$powerSet = powerSet($stateNames);
foreach ($powerSet as $subset) {
$name = generateDFAStateName($subset);
$d = new DFAState($name);
$d->setSubstates($subset);
$dfaStates[$name] = $d;
}
/**
* Take a DFAState and merge all of the states in the transition sets of its
* component substates
*
* For instance, let NFAStates:
* A where d(A, 0) = [B]
* B where d(B, 0) = [A]
*
* then for DFAState:
* AB, we need d(AB, 0) = AB
*/
foreach ($dfaStates as $dfaState) {
foreach ($transitions as $transition) {
$collector = [];
// will hold the set of destination states
foreach ($dfaState->substates as $substateName) {
$nfaState = $nfaStates[$substateName];
// get access to the NFA object by name
$toStates = $nfaState->adjacencyList[$transition];
// merge the states in the adjacencyLists of all the component NFA states
// use array_unique to weed out duplicates
$collector = array_unique(array_merge($collector, $toStates));
}
// need to call sort so that the DFAState names are consistent, i.e. BA vs. AB
sort($collector);
$toState = generateDFAStateName($collector);
$dfaState->setTransition($transition, $toState);
}
}
return $dfaStates;
}