[LON-CAPA-cvs] cvs: loncom /homework/caparesponse caparesponse.pm

[foxr]

foxr		Fri Dec 14 11:17:10 2012 EDT

  Modified files:              
    /loncom/homework/caparesponse	caparesponse.pm 
  Log:
  BZ 6577 - Ensure that computed answers all will have an appropriate number of
  significant figures to pass the validation test...well actualy all user answers
  get extended to the appropriate number of sigfigs so that answers will never
  fail due to significance.
    Students will still need to force answers into a form that has the
  correct number of sigfigs (e.g for 3 sigfigs not 300 but 3.00e2)..
  
  
  
  
Index: loncom/homework/caparesponse/caparesponse.pm
diff -u loncom/homework/caparesponse/caparesponse.pm:1.252 loncom/homework/caparesponse/caparesponse.pm:1.253
--- loncom/homework/caparesponse/caparesponse.pm:1.252	Mon Mar  5 11:50:39 2012
+++ loncom/homework/caparesponse/caparesponse.pm	Fri Dec 14 11:17:09 2012
@@ -446,6 +446,7 @@
     }
 
     my (@final_awards, at final_msgs, at names);
+    # $Apache::lonxml::debug = 1;	# DEBUG
     foreach my $name (keys(%answer)) {
 	&Apache::lonxml::debug(" doing $name with ".join(':',@{ $answer{$name}{'answers'} }));
 	
@@ -456,7 +457,6 @@
 	my ($result, at msgs) = 
 	    &Apache::run::run("&caparesponse_check_list()",$safeeval);
 	&Apache::lonxml::debug("checking $name $result with $response took ".&Time::HiRes::tv_interval($t0));
-        
 	&Apache::lonxml::debug('msgs are '.join(':', at msgs));
 	my ($awards)=split(/:/,$result);
 	my @awards= split(/,/,$awards);
@@ -465,6 +465,7 @@
 	push(@final_msgs,$msg);
 	push(@names,$name);
     }
+    # $Apache::lonxml::debug = 0;	# DEBUG
     my ($ad, $msg, $name) = &Apache::inputtags::finalizeawards(\@final_awards,
 							       \@final_msgs,
 							       \@names,1);
@@ -784,6 +785,19 @@
 		    $ans.=" $cleanunit";
 		}
 	    }
+	    #
+	    # The computer's response must be cast in a form that 
+	    # ensures it has sufficient significant figures.
+	    # the only way to do this is to sprintf it into scientific notation
+	    # due to the ambiguity of trailing zeros.
+	    # See Bug 6577
+	    #
+	    my ($sigMax, $sigmin) = &get_sigrange($Apache::inputtags::params{'sig'});
+	    my $sigfigs = $sigMax-1;
+
+	    for (my $i = 0; $i < scalar @$response; $i++) {
+		$response->[$i] = sprintf('%.' . $sigfigs . 'e', $response->[$i]);
+	    }
 	    my ($ad,$msg)=&check_submission($response,$partid,$id,$tag,
 					    $parstack,$safeeval);
 	    if ($ad ne 'EXACT_ANS' && $ad ne 'APPROX_ANS') {