/**
* Do we have all the necessary inputs to execute one of the potential response trees?
* @param stack_potentialresponse_tree $prt the tree in question.
* @param array $response the response.
* @param bool $acceptvalid if this is true, then we will grade things even
* if the corresponding inputs are only VALID, and not SCORE.
* @return bool can this PRT be executed for that response.
*/
protected function can_execute_prt(stack_potentialresponse_tree $prt, $response, $acceptvalid)
{
// The only way to find out is to actually try evaluating it. This calls
// has_necessary_prt_inputs, and then does the computation, which ensures
// there are no CAS errors.
$result = $this->get_prt_result($prt->get_name(), $response, $acceptvalid);
return null !== $result->valid && !$result->errors;
}
/**
* Helper method to get the list of inputs required by a PRT, given the current
* state of the form.
* @param string $prtname the name of a PRT.
* @return array list of inputs used by this PRT.
*/
protected function get_inputs_used_by_prt($prtname)
{
// Needed for questions with no inputs, (in particular blank starting questions).
if (!property_exists($this->question, 'inputs')) {
return array();
}
if (is_null($this->question->inputs)) {
return array();
}
$inputs = $this->question->inputs;
$inputkeys = array();
if (is_array($inputs)) {
foreach ($inputs as $input) {
$inputkeys[] = $input->name;
}
} else {
return array();
}
// TODO fix this. At the moment it only considers the data from the unedited
// question. We should take into account any changes made since the
// form was first shown, for example adding or removing nodes, or changing
// the things they compare. However, it is not critical.
// If we are creating a new question, or if we add a new prt in the
// question stem, then the PRT will not yet exist, so return an empty array.
if (is_null($this->question->prts) || !array_key_exists($prtname, $this->question->prts)) {
return array();
}
$prt = $this->question->prts[$prtname];
$prtnodes = array();
foreach ($prt->nodes as $name => $node) {
$sans = new stack_cas_casstring($node->sans);
$tans = new stack_cas_casstring($node->tans);
$prtnode = new stack_potentialresponse_node($sans, $tans, $node->answertest, $node->testoptions);
$prtnode->add_branch(1, '+', 0, '', -1, $node->truefeedback, $node->truefeedbackformat, '');
$prtnode->add_branch(0, '+', 0, '', -1, $node->falsefeedback, $node->falsefeedbackformat, '');
$prtnodes[$name] = $prtnode;
}
$feedbackvariables = new stack_cas_keyval($prt->feedbackvariables, null, 0, 't');
$potentialresponsetree = new stack_potentialresponse_tree('', '', false, 0, $feedbackvariables->get_session(), $prtnodes, $prt->firstnodename);
return $potentialresponsetree->get_required_variables($inputkeys);
}
public function test_do_test_3()
{
// Nontrivial use of the feeback variables.
// Error in authoring ends up in loop. STACK should bail.
$options = new stack_options();
$seed = 12345;
$questionvars = new stack_cas_keyval('n:3; p:(x+1)^n; ta:p;', $options, $seed, 't');
// Feeback variables.
$cstrings = array('sa1:sans', 'sa2:expand(sans)');
foreach ($cstrings as $s) {
$cs = new stack_cas_casstring($s);
$cs->get_valid('t');
$s1[] = $cs;
}
$feedbackvars = new stack_cas_session($s1, $options, $seed);
$feedbackvars->get_valid();
// Define the tree itself.
$sans = new stack_cas_casstring('sa1');
$sans->get_valid('t');
$tans = new stack_cas_casstring('ta');
$tans->get_valid('t');
$node = new stack_potentialresponse_node($sans, $tans, 'AlgEquiv', '', true);
$node->add_branch(0, '=', 0, '', -1, 'Test 1 false. Look: \\[@(sa1)^2@ \\neq @(sa2)^2@\\]', FORMAT_HTML, '1-0-0');
$node->add_branch(1, '=', 1, '', 1, 'Test 1 true. ', FORMAT_HTML, '1-0-1');
$potentialresponses[] = $node;
$sans = new stack_cas_casstring('sa2');
$sans->get_valid('t');
$tans = new stack_cas_casstring('ta');
$tans->get_valid('t');
$node = new stack_potentialresponse_node($sans, $tans, 'FacForm', 'x', true);
$node->add_branch(0, '-', 0.7, '', 0, 'Test 2 false.', FORMAT_HTML, '1-1-0');
$node->add_branch(1, '+', 1, '', 3, 'Test 2 true', FORMAT_HTML, '1-1-1');
$potentialresponses[] = $node;
$tree = new stack_potentialresponse_tree('', '', true, 5, $feedbackvars, $potentialresponses, 0);
// Some data from students.
$answers = array('sans' => '(x+1)^3');
$result = $tree->evaluate_response($questionvars->get_session(), $options, $answers, $seed);
$this->assertTrue($result->valid);
$this->assertEquals('', $result->errors);
$this->assertEquals(0.3, $result->score);
$this->assertEquals(0, $result->penalty);
$this->assertEquals(2, count($result->feedback));
$this->assertEquals('Test 1 true.', $result->feedback[0]->feedback);
$this->assertEquals('Test 2 false.', $result->feedback[1]->feedback);
$this->assertEquals(array('1-0-1', 'ATFacForm_notfactored.', '1-1-0', '[PRT-CIRCULARITY]=0'), $result->answernotes);
$this->assertEquals(array('sa1', 'ta'), $tree->get_required_variables(array('sa1', 'sa3', 'ta', 'ssa1', 'a1', 't')));
}
