diff --git a/CMakeLists.txt b/CMakeLists.txt
index db25d7a..590213e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,8 +1,13 @@
 cmake_minimum_required (VERSION 2.6)
 project (qcint C)
-set(qcint_VERSION "3.1.0")
-set(qcint_SOVERSION "3")
-
+set(qcint_VERSION_MAJOR "3")
+set(qcint_VERSION_MINOR "1")
+set(qcint_VERSION_PATCH "1")
+set(qcint_VERSION_TWEAK "0")
+set(qcint_VERSION "${qcint_VERSION_MAJOR}.${qcint_VERSION_MINOR}.${qcint_VERSION_PATCH}")
+set(qcint_SOVERSION "${qcint_VERSION_MAJOR}")
+
+#set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -O2 -DNDEBUG")
 if ("${CMAKE_BUILD_TYPE}" STREQUAL "")
   set(CMAKE_BUILD_TYPE RELWITHDEBINFO)
 endif()
@@ -15,6 +20,7 @@ else()
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -funroll-loops -ftree-vectorize -ffast-math")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-math-errno -fno-strict-overflow -fomit-frame-pointer")
 endif()
+message("${CMAKE_C_FLAGS}")
 
 
 if (${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION}.${CMAKE_PATCH_VERSION} VERSION_GREATER 2.8.3)
@@ -97,9 +103,27 @@ endif(WITH_GTG)
 
 if(PYPZPX)
   add_definitions(-DPYPZPX)
-  message("P orbitals are sorted to (py, pz, px)")
+  message("P orbitals convention (py, pz, px)")
+else()
+  message("P orbitals convention (px, py, pz)")
 endif(PYPZPX)
 
+option(WITH_FORTRAN "Fortran interface" on)
+if(WITH_FORTRAN)
+  add_definitions(-DWITH_FORTRAN)
+  message("Enable Fortran interface")
+else()
+  message("Exclude Fortran interface")
+endif(WITH_FORTRAN)
+
+option(WITH_CINT2_INTERFACE "Old libcint (version 2) interface" on)
+if(WITH_CINT2_INTERFACE)
+  add_definitions(-DWITH_CINT2_INTERFACE)
+  message("Enable old cint (version 2) interface")
+else()
+  message("Exclude old cint (version 2) interface")
+endif(WITH_CINT2_INTERFACE)
+
 option(BUILD_SHARED_LIBS "build shared libraries" 1)
 option(ENABLE_STATIC "Enforce static library build" 0)
 if(ENABLE_STATIC)
diff --git a/ChangeLog b/ChangeLog
index 76e5c0e..1bb14e6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,5 @@
+Version 3.1.1  (2020-08-25):
+	* Fix bug in (py, pz, px) order
 Version 3.1.0  (2020-08-25):
 	* Add convention py, pz, px
 Version 3.0.19  (2019-11-30):
diff --git a/README.md b/README.md
index 2443565..fd9e619 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@ qcint (quick libcint)
 
 An optimized libcint branch for X86 platform
 
-version 3.1.0
+version 3.1.1
 
 2020-08-25
 
diff --git a/src/c2f.c b/src/c2f.c
index 6ff6065..b8ab293 100644
--- a/src/c2f.c
+++ b/src/c2f.c
@@ -22,6 +22,7 @@
  * c to fortran interface
  */
 
+#ifdef WITH_FORTRAN
 #include <stdlib.h>
 #include <math.h>
 #include "cint_bas.h"
@@ -178,3 +179,4 @@ void cintdel_optimizer_(CINTOptPtrAsInteger8 *optptr)
         cintdel_2e_optimizer_(optptr);
 }
 */
+#endif
diff --git a/src/c2f.h b/src/c2f.h
index 32193df..6780d1b 100644
--- a/src/c2f.h
+++ b/src/c2f.h
@@ -18,6 +18,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef WITH_FORTRAN
 #define ALL_CINT_FORTRAN_(NAME) \
 int c##NAME##_sph_(double *out, int *shls, int *atm, int *natm, \
                    int *bas, int *nbas, double *env, size_t optptr_as_integer8) { \
@@ -67,3 +68,10 @@ int c##NAME##_(double *out, int *shls, int *atm, int *natm, \
         return NAME##_spinor((double complex *)out, NULL, shls, \
                              atm, *natm, bas, *nbas, env, NULL, NULL); \
 }
+
+#else
+
+#define ALL_CINT_FORTRAN_(NAME)
+#define ALL_CINT1E_FORTRAN_(NAME)
+
+#endif
diff --git a/src/cart2sph.c b/src/cart2sph.c
index c21b39f..d106d35 100644
--- a/src/cart2sph.c
+++ b/src/cart2sph.c
@@ -2933,9 +2933,9 @@ static double *p_bra_cart2spheric(double *gsph, int nket, double *gcart, int l)
 #ifdef PYPZPX
         int i;
         for (i = 0; i < nket; i++) {
-                gsph[i*nket+0] = gcart[i*nket+1];  // py
-                gsph[i*nket+1] = gcart[i*nket+2];  // pz
-                gsph[i*nket+2] = gcart[i*nket+0];  // px
+                gsph[i*3+0] = gcart[i*3+1];  // py
+                gsph[i*3+1] = gcart[i*3+2];  // pz
+                gsph[i*3+2] = gcart[i*3+0];  // px
         }
         return gsph;
 #else
@@ -8255,8 +8255,18 @@ static double *sph2e_inner(double *gsph, double *gcart,
 {
         int n;
         switch (l) {
+#ifdef PYPZPX
+        case 0:
+                return gcart;
+        case 1:
+                for (n = 0; n < ncall; n++) {
+                        p_ket_cart2spheric(gsph+n*sizsph, gcart+n*sizcart, nbra, nbra, l);
+                }
+                break;
+#else
         case 0: case 1:
                 return gcart;
+#endif
         case 2:
                 for (n = 0; n < ncall; n++) {
                         d_ket_cart2spheric(gsph+n*sizsph, gcart+n*sizcart, nbra, nbra, l);
diff --git a/src/misc.h b/src/misc.h
index ffd1006..7142859 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -37,6 +37,7 @@ double CINTsquare_dist(const double *r1, const double *r2);
 double CINTgto_norm(int n, double a);
 
 
+#ifdef WITH_CINT2_INTERFACE
 #define ALL_CINT(NAME) \
 int c##NAME##_cart(double *out, int *shls, int *atm, int natm, \
             int *bas, int nbas, double *env, CINTOpt *opt) { \
@@ -79,3 +80,10 @@ int c##NAME(double *out, int *shls, int *atm, int natm, \
         return NAME##_spinor((double complex *)out, NULL, shls, \
                              atm, natm, bas, nbas, env, NULL, NULL); \
 }
+
+#else
+
+#define ALL_CINT(NAME)
+#define ALL_CINT1E(NAME)
+
+#endif  // WITH_CINT2_INTERFACE