fix problems with heaviside(0) = 1/2

Author: fabian.froehlich

symbolic/am_if.m

@@ -2,5 +2,17 @@
 % syms x y z
 % f = symfun(sym('am_if(x,y,z)'),[x y z]);
 % fun = f(condition, truepart, falsepart);
-fun = falsepart + heaviside(condition)*(truepart-falsepart); 
+if(islogical(condition))
+    if(condition)
+        fun = truepart;
+    else
+        fun = falsepart;
+    end
+else
+    if(logical(condition~=0))
+        fun = falsepart + heaviside(condition)*(truepart-falsepart);
+    else
+        fun = falsepart;
+    end
+end
 end