[WWcvs] webwork2: fixed divide-by-zero error when calculating index.

[Sam H. v. a. <we...@ma...>]

Log Message:
-----------
fixed divide-by-zero error when calculating index.

Modified Files:
--------------
    webwork2/lib/WeBWorK/ContentGenerator/Instructor:
        Scoring.pm

Revision Data
-------------
Index: Scoring.pm
===================================================================
RCS file: /webwork/cvs/system/webwork2/lib/WeBWorK/ContentGenerator/Instructor/Scoring.pm,v
retrieving revision 1.50
retrieving revision 1.51
diff -Llib/WeBWorK/ContentGenerator/Instructor/Scoring.pm -Llib/WeBWorK/ContentGenerator/Instructor/Scoring.pm -u -r1.50 -r1.51
--- lib/WeBWorK/ContentGenerator/Instructor/Scoring.pm
+++ lib/WeBWorK/ContentGenerator/Instructor/Scoring.pm
@@ -484,7 +484,7 @@
 	if ($scoringItems->{successIndex}) {
 		for (my $user = 0; $user < @sortedUserIDs; $user++) {
 			my $avg_num_attempts = ($num_of_problems) ? $numberOfAttempts{$user}/$num_of_problems : 0;
-			$userSuccessIndex{$user} = ($avg_num_attempts) ? ($userStatusTotals{$user}/$valueTotal)**2/$avg_num_attempts : 0;						
+			$userSuccessIndex{$user} = ($avg_num_attempts && $valueTotal) ? ($userStatusTotals{$user}/$valueTotal)**2/$avg_num_attempts : 0;						
 		}
 	}
 	# write the status totals