Merge pull request #731 from MITx/feature/ichuang/symmath_improvements

improvements in symbolic math checking.

Merging now because it is needed for Physics courses.

lms/djangoapps/courseware/tabs.py

@@ -173,7 +173,7 @@ def get_course_tabs(user, course, active_page):
     """
     Return the tabs to show a particular user, as a list of CourseTab items.
     """
-    if not course.tabs:
+    if not hasattr(course,'tabs') or not course.tabs:
         return get_default_tabs(user, course, active_page)
 
     # TODO (vshnayder): There needs to be a place to call this right after course

lms/lib/symmath/formula.py

@@ -105,6 +105,7 @@ def my_sympify(expr, normphase=False, matrix=False, abcsym=False, do_qubit=False
                   'e': sympy.E,			# for exp
                   'i': sympy.I,			# lowercase i is also sqrt(-1)
                   'Q': sympy.Symbol('Q'),	 # otherwise it is a sympy "ask key"
+                  'I': sympy.Symbol('I'),	 # otherwise it is sqrt(-1)
                   #'X':sympy.sympify('Matrix([[0,1],[1,0]])'),
                   #'Y':sympy.sympify('Matrix([[0,-I],[I,0]])'),
                   #'Z':sympy.sympify('Matrix([[1,0],[0,-1]])'),
@@ -273,11 +274,16 @@ class formula(object):
             if not self.is_mathml():
                 return my_sympify(self.expr)
             if self.is_presentation_mathml():
+                cmml = None
                 try:
                     cmml = self.cmathml
                     xml = etree.fromstring(str(cmml))
                 except Exception, err:
-                    raise Exception, 'Err %s while converting cmathml to xml; cmml=%s' % (err, cmml)
+                    if 'conversion from Presentation MathML to Content MathML was not successful' in cmml:
+                        msg = "Illegal math expression"
+                    else:
+                        msg = 'Err %s while converting cmathml to xml; cmml=%s' % (err, cmml)
+                    raise Exception, msg
                 xml = self.fix_greek_in_mathml(xml)
                 self.the_sympy = self.make_sympy(xml[0])
             else:
@@ -320,6 +326,24 @@ class formula(object):
                   'power': sympy.Pow,
                   'sin': sympy.sin,
                   'cos': sympy.cos,
+                  'tan': sympy.tan,
+                  'cot': sympy.cot,
+                  'sinh': sympy.sinh,
+                  'cosh': sympy.cosh,
+                  'coth': sympy.coth,
+                  'tanh': sympy.tanh,
+                  'asin': sympy.asin,
+                  'acos': sympy.acos,
+                  'atan': sympy.atan,
+                  'atan2': sympy.atan2,
+                  'acot': sympy.acot,
+                  'asinh': sympy.asinh,
+                  'acosh': sympy.acosh,
+                  'atanh': sympy.atanh,
+                  'acoth': sympy.acoth,
+                  'exp': sympy.exp,
+                  'log': sympy.log,
+                  'ln': sympy.ln,
                    }
 
         # simple sumbols
@@ -385,8 +409,7 @@ class formula(object):
                 if 'hat' in usym:
                     sym = my_sympify(usym)
                 else:
-                    if usym == 'i': print "options=", self.options
-                    if usym == 'i' and 'imaginary' in self.options:	 # i = sqrt(-1)
+                    if usym == 'i' and self.options is not None and 'imaginary' in self.options:	 # i = sqrt(-1)
                         sym = sympy.I
                     else:
                         sym = sympy.Symbol(str(usym))

lms/lib/symmath/symmath_check.py

@@ -141,12 +141,19 @@ def check(expect, given, numerical=False, matrix=False, normphase=False, abcsym=
     return {'ok': False, 'msg': msg}
 
 #-----------------------------------------------------------------------------
+# helper function to convert all <p> to <span class='inline-error'>
+
+def make_error_message(msg):
+    # msg = msg.replace('<p>','<p><span class="inline-error">').replace('</p>','</span></p>')
+    msg = '<div class="capa_alert">%s</div>' % msg
+    return msg
+
+#-----------------------------------------------------------------------------
 # Check function interface, which takes pmathml input
 #
 # This is one of the main entry points to call.
 
-
-def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
+def symmath_check(expect, ans, dynamath=None, options=None, debug=None, xml=None):
     '''
     Check a symbolic mathematical expression using sympy.
     The input may be presentation MathML.  Uses formula.
@@ -159,17 +166,23 @@ def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
     threshold = 1.0e-3
     DEBUG = debug
 
+    if xml is not None:
+        DEBUG = xml.get('debug',False)	# override debug flag using attribute in symbolicmath xml
+        if DEBUG in ['0','False']:
+            DEBUG = False
+
     # options
     do_matrix = 'matrix' in (options or '')
     do_qubit = 'qubit' in (options or '')
     do_imaginary = 'imaginary' in (options or '')
+    do_numerical = 'numerical' in (options or '')
 
     # parse expected answer
     try:
         fexpect = my_sympify(str(expect), matrix=do_matrix, do_qubit=do_qubit)
     except Exception, err:
         msg += '<p>Error %s in parsing OUR expected answer "%s"</p>' % (err, expect)
-        return {'ok': False, 'msg': msg}
+        return {'ok': False, 'msg': make_error_message(msg)}
 
     # if expected answer is a number, try parsing provided answer as a number also
     try:
@@ -184,6 +197,13 @@ def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
             msg += '<p>You entered: %s</p>' % to_latex(fans)
             return {'ok': False, 'msg': msg}
 
+    if do_numerical:		# numerical answer expected - force numerical comparison
+        if abs(abs(fans - fexpect) / fexpect) < threshold:
+            return {'ok': True, 'msg': msg}
+        else:
+            msg += '<p>You entered: %s (note that a numerical answer is expected)</p>' % to_latex(fans)
+            return {'ok': False, 'msg': msg}
+
     if fexpect == fans:
         msg += '<p>You entered: %s</p>' % to_latex(fans)
         return {'ok': True, 'msg': msg}
@@ -205,16 +225,18 @@ def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
         msg += '<p>You entered: %s</p>' % to_latex(f.sympy)
     except Exception, err:
         log.exception("Error evaluating expression '%s' as a valid equation" % ans)
-        msg += "<p>Error %s in evaluating your expression '%s' as a valid equation</p>" % (str(err).replace('<', '&lt;'),
-                                                                                           ans)
+        msg += "<p>Error in evaluating your expression '%s' as a valid equation</p>" % (ans)
+        if "Illegal math" in str(err):
+            msg += "<p>Illegal math expression</p>"
         if DEBUG:
+            msg += 'Error: %s' % str(err).replace('<', '&lt;')
             msg += '<hr>'
             msg += '<p><font color="blue">DEBUG messages:</p>'
             msg += "<p><pre>%s</pre></p>" % traceback.format_exc()
             msg += '<p>cmathml=<pre>%s</pre></p>' % f.cmathml.replace('<', '&lt;')
             msg += '<p>pmathml=<pre>%s</pre></p>' % mmlans.replace('<', '&lt;')
             msg += '<hr>'
-        return {'ok': False, 'msg': msg}
+        return {'ok': False, 'msg': make_error_message(msg)}
 
     # compare with expected
     if hasattr(fexpect, 'is_number') and fexpect.is_number:
@@ -226,7 +248,7 @@ def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
         msg += "<p>given = %s</p>" % repr(ans)
         msg += "<p>fsym = %s</p>" % repr(fsym)
         # msg += "<p>cmathml = <pre>%s</pre></p>" % str(f.cmathml).replace('<','&lt;')
-        return {'ok': False, 'msg': msg}
+        return {'ok': False, 'msg': make_error_message(msg)}
 
     if fexpect == fsym:
         return {'ok': True, 'msg': msg}
@@ -239,11 +261,11 @@ def symmath_check(expect, ans, dynamath=None, options=None, debug=None):
                 return {'ok': True, 'msg': msg}
         except sympy.ShapeError:
             msg += "<p>Error - your input vector or matrix has the wrong dimensions"
-            return {'ok': False, 'msg': msg}
+            return {'ok': False, 'msg': make_error_message(msg)}
         except Exception, err:
             msg += "<p>Error %s in comparing expected (a list) and your answer</p>" % str(err).replace('<', '&lt;')
             if DEBUG: msg += "<p/><pre>%s</pre>" % traceback.format_exc()
-            return {'ok': False, 'msg': msg}
+            return {'ok': False, 'msg': make_error_message(msg)}
 
     #diff = (fexpect-fsym).simplify()
     #fsym = fsym.simplify()