Added error message for the case of parameters that are not supported.

pdeutils/quadrature/simplexQuadratureRule.m

@@ -27,6 +27,9 @@ function Q = simplexQuadratureRule(dim, order)
         weights = [A B B B C C C];
 
         order = 5;
+    else
+        error( 'The parameters (dim=%d, order=%d) are not supported.', ...
+                dim, order );
     end
 
     Q = struct('size', length(weights), 'points', points, 'weights', weights, 'order', order);