--- loncom/homework/default_homework.lcpm	2011/05/22 03:04:51	1.155
+++ loncom/homework/default_homework.lcpm	2011/06/07 22:07:09	1.156
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
 #
-# $Id: default_homework.lcpm,v 1.155 2011/05/22 03:04:51 www Exp $
+# $Id: default_homework.lcpm,v 1.156 2011/06/07 22:07:09 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -309,12 +309,19 @@ sub caparesponse_check_list {
 
     &LONCAPA_INTERNAL_DEBUG("Initial final response :$responses->[0][-1]:");
     my $unit;
+    my ($allowalgebra)=(&parameter_setting('allowalgebra',&currentpart())=~/^(yes|1|on)$/i);
     if ($type eq 'float' || $type eq '') {
 	#for numerical problems split off the unit
-#	if ( $responses->[0][-1]=~ /(.*[^\s])\s+([^\s]+)/ ) {
-        if ( $responses->[0][-1]=~ /^([\d\.\,\s\$]*(?:(?:[xX\*]10[\^\*]*|[eE]*)[\+\-]*\d*)*(?:^|\S)\d+)([\$\s\w\^\*\/\(\)\+\-]*[^\d\.\s\,][\$\s\w\^\*\/\(\)\+\-]*)$/ ) {
-	    $responses->[0][-1]=$1;
-	    $unit=&capa_formula_fix($2);
+        my $part1;
+        my $part2;
+        if ($allowalgebra) {
+           ($part1,$part2)=($responses->[0][-1]=~ /^(.*[^\s])\s+([^\s]+)$/); 
+        } else {
+           ($part1,$part2)=($responses->[0][-1]=~ /^([\d\.\,\s\$]*(?:(?:[xX\*]10[\^\*]*|[eE]*)[\+\-]*\d*)*(?:^|\S)\d+)([\$\s\w\^\*\/\(\)\+\-]*[^\d\.\s\,][\$\s\w\^\*\/\(\)\+\-]*)$/);
+        }
+        if ($part1 && $part2) {
+	    $responses->[0][-1]=$part1;
+	    $unit=&capa_formula_fix($part2);
             &LONCAPA_INTERNAL_DEBUG("Found unit :$unit:");
 	}
     }
@@ -344,6 +351,10 @@ sub caparesponse_check_list {
           if (($element==0) && ($unit!~/\w/) && ($answerunit=~/\w/)) {
              $appendunit=$answerunit;
           }
+# Do the math for the student if allowed
+          if ($allowalgebra) {
+             $element=&cas('maxima',$element);
+          }
           if ($appendunit ne '') {
               $element .= " $appendunit";
           }