diff --git a/CMakeLists.txt b/CMakeLists.txt
index 08a71085..e05e508d 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -195,7 +195,7 @@ set(THIRDPARTY_INSTALL_PATH ${THIRDPARTY_BASE_PATH})
 
 if(NOT WIN32)
 #CoinUtils
-if (CoinUtils or MP)
+if (CoinUtils)
 include(ExternalProject)
 #CoinUtils
 message(STATUS "Enable CoinUtils")
diff --git a/examples/Gravity_test.cpp b/examples/Gravity_test.cpp
index 74231528..7feec051 100755
--- a/examples/Gravity_test.cpp
+++ b/examples/Gravity_test.cpp
@@ -22,11 +22,30 @@
 using namespace std;
 using namespace gravity;
 
+TEST_CASE("testing Gurobi's compound NL") {
+    Model<> M;
+    M.set_name("M");
+    var<> x("x", -2,2);
+    var<> y("y", 0,0);
+    var<> z("z", pi/2.,pi/2.);
+    var<> resvar("resvar", -10,10);
+    M.add(resvar);
+    M.add(x);
+    M.add(y);
+    M.add(z);
+    Constraint<> C("C");
+    C = cos(cos(y) - sin(z + cos(y))) - x - 2 - resvar;
+    M.add(C==0);
+    M.max(resvar);
+    solver<> GRB(M,gurobi);
+    double solver_time_start = get_wall_time();
+    GRB.run();
+}
 
 #ifdef USE_MP
 TEST_CASE("testing readNL() function") {
     Model<> M;
-    string NL_file = string(prj_dir)+"/data_sets/NL/hvycrash.nl";
+    string NL_file = string(prj_dir)+"/data_sets/NL/camshape100.nl";
     int status = M.readNL(NL_file);
     solver<> GRB(M,gurobi);
     double solver_time_start = get_wall_time();
diff --git a/include/gravity/func.h b/include/gravity/func.h
index 2ac1beec..07b3a890 100755
--- a/include/gravity/func.h
+++ b/include/gravity/func.h
@@ -4810,6 +4810,15 @@ namespace gravity {
                 
             }
             if(_expr){
+                if(_expr->_coef != unit<type>().eval()){
+                    str += " ( PLUS     , -1  , +"+to_string(current_root_id)+" )\n";
+                    parent_id++;
+                    str += " ( MULTIPLY     , -1  , +"+to_string(parent_id)+" )\n";
+                    parent_id++;
+                    current_root_id = parent_id;
+                    str += " ( CONSTANT     , " + to_string(_expr->_coef) + "  , +"+to_string(parent_id)+" )\n";
+                    parent_id++;
+                }
                 str += getNLexpr(_expr, current_root_id, parent_id, i);
             }
             return str;