diff --git a/src/ASPHERE-POINT/fix_nh_asphere.cpp b/src/ASPHERE-POINT/fix_nh_asphere.cpp
index f491fe5787..1d791c513d 100644
--- a/src/ASPHERE-POINT/fix_nh_asphere.cpp
+++ b/src/ASPHERE-POINT/fix_nh_asphere.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE-POINT/fix_nph_asphere.cpp b/src/ASPHERE-POINT/fix_nph_asphere.cpp
index 025137def2..4e6339dfe4 100644
--- a/src/ASPHERE-POINT/fix_nph_asphere.cpp
+++ b/src/ASPHERE-POINT/fix_nph_asphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE-POINT/fix_npt_asphere.cpp b/src/ASPHERE-POINT/fix_npt_asphere.cpp
index 44ed01ea45..3b2d24ef26 100644
--- a/src/ASPHERE-POINT/fix_npt_asphere.cpp
+++ b/src/ASPHERE-POINT/fix_npt_asphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE-POINT/fix_nve_asphere.cpp b/src/ASPHERE-POINT/fix_nve_asphere.cpp
index 5fd824fd15..903f533241 100644
--- a/src/ASPHERE-POINT/fix_nve_asphere.cpp
+++ b/src/ASPHERE-POINT/fix_nve_asphere.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define INERTIA 0.2          // moment of inertia prefactor for ellipsoid
 
diff --git a/src/ASPHERE-POINT/fix_nvt_asphere.cpp b/src/ASPHERE-POINT/fix_nvt_asphere.cpp
index 4137941be9..28428234b2 100644
--- a/src/ASPHERE-POINT/fix_nvt_asphere.cpp
+++ b/src/ASPHERE-POINT/fix_nvt_asphere.cpp
@@ -18,6 +18,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_nh_asphere.cpp b/src/ASPHERE/fix_nh_asphere.cpp
index 3d91262345..a8290924da 100644
--- a/src/ASPHERE/fix_nh_asphere.cpp
+++ b/src/ASPHERE/fix_nh_asphere.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_nph_asphere.cpp b/src/ASPHERE/fix_nph_asphere.cpp
index 094e0f06a6..76a3495693 100644
--- a/src/ASPHERE/fix_nph_asphere.cpp
+++ b/src/ASPHERE/fix_nph_asphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_npt_asphere.cpp b/src/ASPHERE/fix_npt_asphere.cpp
index 2c3c70e948..6296302e67 100644
--- a/src/ASPHERE/fix_npt_asphere.cpp
+++ b/src/ASPHERE/fix_npt_asphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_nve_asphere.cpp b/src/ASPHERE/fix_nve_asphere.cpp
index ac3abea6bc..6504219245 100644
--- a/src/ASPHERE/fix_nve_asphere.cpp
+++ b/src/ASPHERE/fix_nve_asphere.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define INERTIA 0.2          // moment of inertia prefactor for ellipsoid
 
diff --git a/src/ASPHERE/fix_nve_asphere_noforce.cpp b/src/ASPHERE/fix_nve_asphere_noforce.cpp
index 42793723b5..2fb8bd98ef 100644
--- a/src/ASPHERE/fix_nve_asphere_noforce.cpp
+++ b/src/ASPHERE/fix_nve_asphere_noforce.cpp
@@ -24,6 +24,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_nve_line.cpp b/src/ASPHERE/fix_nve_line.cpp
index 682119c6a1..5f022db24a 100644
--- a/src/ASPHERE/fix_nve_line.cpp
+++ b/src/ASPHERE/fix_nve_line.cpp
@@ -22,6 +22,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 #define INERTIA (1.0/12.0)     // moment of inertia prefactor for line segment
diff --git a/src/ASPHERE/fix_nve_tri.cpp b/src/ASPHERE/fix_nve_tri.cpp
index ca83afcdbb..92fc1320d0 100644
--- a/src/ASPHERE/fix_nve_tri.cpp
+++ b/src/ASPHERE/fix_nve_tri.cpp
@@ -22,6 +22,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/ASPHERE/fix_nvt_asphere.cpp b/src/ASPHERE/fix_nvt_asphere.cpp
index 8578da033e..4ec80141c0 100644
--- a/src/ASPHERE/fix_nvt_asphere.cpp
+++ b/src/ASPHERE/fix_nvt_asphere.cpp
@@ -18,6 +18,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/COLLOID/fix_wall_colloid.cpp b/src/COLLOID/fix_wall_colloid.cpp
index e4267358c8..33717104c2 100644
--- a/src/COLLOID/fix_wall_colloid.cpp
+++ b/src/COLLOID/fix_wall_colloid.cpp
@@ -25,6 +25,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/GPU/fix_gpu.cpp b/src/GPU/fix_gpu.cpp
index fa02ea3cb6..a5dfb2ad1f 100644
--- a/src/GPU/fix_gpu.cpp
+++ b/src/GPU/fix_gpu.cpp
@@ -28,6 +28,7 @@
 #include "neighbor.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{GPU_FORCE, GPU_NEIGH, GPU_HYB_NEIGH};
 
diff --git a/src/GPU/fix_report_balance.cpp b/src/GPU/fix_report_balance.cpp
index 9fd546bc2f..3fd8d4aade 100644
--- a/src/GPU/fix_report_balance.cpp
+++ b/src/GPU/fix_report_balance.cpp
@@ -34,6 +34,7 @@
 #include "output.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/GRANULAR/fix_freeze.cpp b/src/GRANULAR/fix_freeze.cpp
index 848574e5fe..40672035e9 100644
--- a/src/GRANULAR/fix_freeze.cpp
+++ b/src/GRANULAR/fix_freeze.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/GRANULAR/fix_pour.cpp b/src/GRANULAR/fix_pour.cpp
index fe0ce40f31..c775b16034 100644
--- a/src/GRANULAR/fix_pour.cpp
+++ b/src/GRANULAR/fix_pour.cpp
@@ -32,6 +32,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 #define EPSILON 0.001
diff --git a/src/GRANULAR/fix_wall_gran.cpp b/src/GRANULAR/fix_wall_gran.cpp
index 2f580c54d7..e3c61c5896 100644
--- a/src/GRANULAR/fix_wall_gran.cpp
+++ b/src/GRANULAR/fix_wall_gran.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{XPLANE=0,YPLANE=1,ZPLANE=2,ZCYLINDER};    // XYZ PLANE need to be 0,1,2
diff --git a/src/MANYBODY/fix_qeq_comb.cpp b/src/MANYBODY/fix_qeq_comb.cpp
index 7d36ee157e..f04a93bd1f 100644
--- a/src/MANYBODY/fix_qeq_comb.cpp
+++ b/src/MANYBODY/fix_qeq_comb.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/MC/fix_bond_break.cpp b/src/MC/fix_bond_break.cpp
index 888c247da7..a68c173d29 100755
--- a/src/MC/fix_bond_break.cpp
+++ b/src/MC/fix_bond_break.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/MC/fix_bond_create.cpp b/src/MC/fix_bond_create.cpp
index 042ff80dbc..52f3ab045d 100755
--- a/src/MC/fix_bond_create.cpp
+++ b/src/MC/fix_bond_create.cpp
@@ -30,6 +30,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define BIG 1.0e20
 
diff --git a/src/MC/fix_bond_swap.cpp b/src/MC/fix_bond_swap.cpp
index 4003e437f8..c02f3fcd3d 100644
--- a/src/MC/fix_bond_swap.cpp
+++ b/src/MC/fix_bond_swap.cpp
@@ -35,6 +35,7 @@
 #include "update.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/MC/fix_gcmc.cpp b/src/MC/fix_gcmc.cpp
index 9c8654100d..bc450dbacc 100644
--- a/src/MC/fix_gcmc.cpp
+++ b/src/MC/fix_gcmc.cpp
@@ -35,6 +35,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/PERI/fix_peri_neigh.cpp b/src/PERI/fix_peri_neigh.cpp
index eb7d8c8539..5a504b7330 100644
--- a/src/PERI/fix_peri_neigh.cpp
+++ b/src/PERI/fix_peri_neigh.cpp
@@ -33,6 +33,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/POEMS/fix_poems.cpp b/src/POEMS/fix_poems.cpp
index f783528c0b..c718f72c05 100644
--- a/src/POEMS/fix_poems.cpp
+++ b/src/POEMS/fix_poems.cpp
@@ -37,6 +37,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAXBODY 2         // currently 2 since only linear chains allowed
 #define DELTA 128
diff --git a/src/REAX/fix_reax_bonds.cpp b/src/REAX/fix_reax_bonds.cpp
index ddd5b5eaa3..5f1c6d60d5 100644
--- a/src/REAX/fix_reax_bonds.cpp
+++ b/src/REAX/fix_reax_bonds.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/REPLICA/fix_event.cpp b/src/REPLICA/fix_event.cpp
index 1277135502..700b9e3341 100644
--- a/src/REPLICA/fix_event.cpp
+++ b/src/REPLICA/fix_event.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/REPLICA/fix_event_prd.cpp b/src/REPLICA/fix_event_prd.cpp
index 84dedd18fd..e86f259721 100644
--- a/src/REPLICA/fix_event_prd.cpp
+++ b/src/REPLICA/fix_event_prd.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/REPLICA/fix_event_tad.cpp b/src/REPLICA/fix_event_tad.cpp
index 7574b4873f..e1b4d10cca 100644
--- a/src/REPLICA/fix_event_tad.cpp
+++ b/src/REPLICA/fix_event_tad.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/REPLICA/fix_neb.cpp b/src/REPLICA/fix_neb.cpp
index d244ea7a8e..73116fac25 100644
--- a/src/REPLICA/fix_neb.cpp
+++ b/src/REPLICA/fix_neb.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/SHOCK/fix_append_atoms.cpp b/src/SHOCK/fix_append_atoms.cpp
index 4a87d616f6..b77067b939 100644
--- a/src/SHOCK/fix_append_atoms.cpp
+++ b/src/SHOCK/fix_append_atoms.cpp
@@ -27,6 +27,7 @@
 #include "force.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define BIG      1.0e30
 #define EPSILON  1.0e-6
diff --git a/src/SHOCK/fix_msst.cpp b/src/SHOCK/fix_msst.cpp
index 267989f309..04d207880d 100644
--- a/src/SHOCK/fix_msst.cpp
+++ b/src/SHOCK/fix_msst.cpp
@@ -35,6 +35,7 @@
 #include "thermo.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/SHOCK/fix_nphug.cpp b/src/SHOCK/fix_nphug.cpp
index 32230940d5..746498915b 100644
--- a/src/SHOCK/fix_nphug.cpp
+++ b/src/SHOCK/fix_nphug.cpp
@@ -27,6 +27,7 @@
 #include "math.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{ISO,ANISO,TRICLINIC}; // same as fix_nh.cpp
 
diff --git a/src/SHOCK/fix_wall_piston.cpp b/src/SHOCK/fix_wall_piston.cpp
index 3b66583715..f9fc94c020 100644
--- a/src/SHOCK/fix_wall_piston.cpp
+++ b/src/SHOCK/fix_wall_piston.cpp
@@ -27,6 +27,7 @@
 #include "math_const.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/SRD/fix_srd.cpp b/src/SRD/fix_srd.cpp
index b673b9b7b5..d18f2bab9b 100644
--- a/src/SRD/fix_srd.cpp
+++ b/src/SRD/fix_srd.cpp
@@ -41,6 +41,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{SLIP,NOSLIP};
diff --git a/src/SRD/fix_wall_srd.cpp b/src/SRD/fix_wall_srd.cpp
index fe38da8b4e..50b3965c11 100644
--- a/src/SRD/fix_wall_srd.cpp
+++ b/src/SRD/fix_wall_srd.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{XLO,XHI,YLO,YHI,ZLO,ZHI};
 enum{NONE,EDGE,CONSTANT,VARIABLE};
diff --git a/src/USER-ATC/fix_atc.cpp b/src/USER-ATC/fix_atc.cpp
index dde062dc40..62e4979216 100644
--- a/src/USER-ATC/fix_atc.cpp
+++ b/src/USER-ATC/fix_atc.cpp
@@ -34,6 +34,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS; 
+using namespace FixConst;
 
 // main page of doxygen documentation
 /*! \mainpage AtC : Atom-to-Continuum methods
diff --git a/src/USER-AWPMD/fix_nve_awpmd.cpp b/src/USER-AWPMD/fix_nve_awpmd.cpp
index 5aee8958ae..8fbf2fa8a5 100644
--- a/src/USER-AWPMD/fix_nve_awpmd.cpp
+++ b/src/USER-AWPMD/fix_nve_awpmd.cpp
@@ -29,6 +29,7 @@
 #include "TCP/wpmd_split.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-EFF/fix_langevin_eff.cpp b/src/USER-EFF/fix_langevin_eff.cpp
index faff9909d1..88f38ab83a 100644
--- a/src/USER-EFF/fix_langevin_eff.cpp
+++ b/src/USER-EFF/fix_langevin_eff.cpp
@@ -38,6 +38,7 @@
 #include "group.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 enum{CONSTANT,EQUAL,ATOM};
diff --git a/src/USER-EFF/fix_nh_eff.cpp b/src/USER-EFF/fix_nh_eff.cpp
index 12bcb90760..4258a081ba 100644
--- a/src/USER-EFF/fix_nh_eff.cpp
+++ b/src/USER-EFF/fix_nh_eff.cpp
@@ -24,6 +24,7 @@
 #include "domain.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 
diff --git a/src/USER-EFF/fix_nph_eff.cpp b/src/USER-EFF/fix_nph_eff.cpp
index 7cf5be647d..f75dbee35a 100644
--- a/src/USER-EFF/fix_nph_eff.cpp
+++ b/src/USER-EFF/fix_nph_eff.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-EFF/fix_npt_eff.cpp b/src/USER-EFF/fix_npt_eff.cpp
index 3b27e9b967..53b3ab11e2 100644
--- a/src/USER-EFF/fix_npt_eff.cpp
+++ b/src/USER-EFF/fix_npt_eff.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-EFF/fix_nve_eff.cpp b/src/USER-EFF/fix_nve_eff.cpp
index 9b4613df3e..6ddff5e30c 100644
--- a/src/USER-EFF/fix_nve_eff.cpp
+++ b/src/USER-EFF/fix_nve_eff.cpp
@@ -28,6 +28,7 @@
 #include "domain.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-EFF/fix_nvt_eff.cpp b/src/USER-EFF/fix_nvt_eff.cpp
index a40cd4aefa..0236f406e0 100644
--- a/src/USER-EFF/fix_nvt_eff.cpp
+++ b/src/USER-EFF/fix_nvt_eff.cpp
@@ -19,6 +19,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-EFF/fix_nvt_sllod_eff.cpp b/src/USER-EFF/fix_nvt_sllod_eff.cpp
index 0d38c19049..adb3dd8221 100644
--- a/src/USER-EFF/fix_nvt_sllod_eff.cpp
+++ b/src/USER-EFF/fix_nvt_sllod_eff.cpp
@@ -24,6 +24,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NO_REMAP,X_REMAP,V_REMAP};                   // same as fix_deform.cpp
 
diff --git a/src/USER-EFF/fix_temp_rescale_eff.cpp b/src/USER-EFF/fix_temp_rescale_eff.cpp
index b6f4d585f7..8d9fce342a 100644
--- a/src/USER-EFF/fix_temp_rescale_eff.cpp
+++ b/src/USER-EFF/fix_temp_rescale_eff.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 
diff --git a/src/USER-MISC/fix_addtorque.cpp b/src/USER-MISC/fix_addtorque.cpp
index bf1a8b58aa..dd9ef8ffc4 100644
--- a/src/USER-MISC/fix_addtorque.cpp
+++ b/src/USER-MISC/fix_addtorque.cpp
@@ -31,6 +31,7 @@
 #include "force.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,CONSTANT,EQUAL,ATOM};
 
diff --git a/src/USER-MISC/fix_imd.cpp b/src/USER-MISC/fix_imd.cpp
index 462883a207..4f02a6f5df 100644
--- a/src/USER-MISC/fix_imd.cpp
+++ b/src/USER-MISC/fix_imd.cpp
@@ -429,6 +429,7 @@ static void  imdsock_destroy(void *);
  ***************************************************************/
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* struct for packed data communication of coordinates and forces. */
 struct commdata { 
diff --git a/src/USER-MISC/fix_smd.cpp b/src/USER-MISC/fix_smd.cpp
index 836a11cd64..25d26b98e0 100644
--- a/src/USER-MISC/fix_smd.cpp
+++ b/src/USER-MISC/fix_smd.cpp
@@ -29,6 +29,7 @@
 #include "group.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum { SMD_NONE=0, 
        SMD_TETHER=1<<0, SMD_COUPLE=1<<1, 
diff --git a/src/USER-MISC/fix_spring_pull.cpp b/src/USER-MISC/fix_spring_pull.cpp
index 709903f779..bb25a5af3b 100644
--- a/src/USER-MISC/fix_spring_pull.cpp
+++ b/src/USER-MISC/fix_spring_pull.cpp
@@ -27,6 +27,7 @@
 #include "group.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define SMALL 1.0e-10
 
diff --git a/src/USER-OMP/fix_gravity_omp.cpp b/src/USER-OMP/fix_gravity_omp.cpp
index c4f4b39b6c..ab39f41428 100644
--- a/src/USER-OMP/fix_gravity_omp.cpp
+++ b/src/USER-OMP/fix_gravity_omp.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{CHUTE,SPHERICAL,GRADIENT,VECTOR};
 
diff --git a/src/USER-OMP/fix_nve_sphere_omp.cpp b/src/USER-OMP/fix_nve_sphere_omp.cpp
index 93af055f81..6ac5afe55e 100644
--- a/src/USER-OMP/fix_nve_sphere_omp.cpp
+++ b/src/USER-OMP/fix_nve_sphere_omp.cpp
@@ -23,6 +23,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define INERTIA 0.4          // moment of inertia prefactor for sphere
 
diff --git a/src/USER-OMP/fix_omp.cpp b/src/USER-OMP/fix_omp.cpp
index 29c577c489..fc8544817c 100644
--- a/src/USER-OMP/fix_omp.cpp
+++ b/src/USER-OMP/fix_omp.cpp
@@ -41,6 +41,7 @@
 #include <stdio.h>
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 static int get_tid()
 {
diff --git a/src/USER-OMP/fix_peri_neigh_omp.cpp b/src/USER-OMP/fix_peri_neigh_omp.cpp
index b8e07403a9..2b3780f41e 100644
--- a/src/USER-OMP/fix_peri_neigh_omp.cpp
+++ b/src/USER-OMP/fix_peri_neigh_omp.cpp
@@ -22,6 +22,7 @@
 #include "neigh_request.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-OMP/fix_qeq_comb_omp.cpp b/src/USER-OMP/fix_qeq_comb_omp.cpp
index f0a477fef6..4f975bc7d8 100644
--- a/src/USER-OMP/fix_qeq_comb_omp.cpp
+++ b/src/USER-OMP/fix_qeq_comb_omp.cpp
@@ -31,6 +31,7 @@
 #include <string.h>
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-OMP/fix_shear_history_omp.cpp b/src/USER-OMP/fix_shear_history_omp.cpp
index 4655dd1af7..d539b69709 100644
--- a/src/USER-OMP/fix_shear_history_omp.cpp
+++ b/src/USER-OMP/fix_shear_history_omp.cpp
@@ -29,6 +29,7 @@
 #endif
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAXTOUCH 15
 
diff --git a/src/USER-OMP/fix_wall_gran_omp.cpp b/src/USER-OMP/fix_wall_gran_omp.cpp
index 5857c921a6..5b38d41159 100644
--- a/src/USER-OMP/fix_wall_gran_omp.cpp
+++ b/src/USER-OMP/fix_wall_gran_omp.cpp
@@ -21,6 +21,7 @@
 #include "update.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 
 enum{XPLANE,YPLANE,ZPLANE,ZCYLINDER};    // XYZ PLANE need to be 0,1,2
diff --git a/src/USER-REAXC/fix_qeq_reax.cpp b/src/USER-REAXC/fix_qeq_reax.cpp
index b68da226f4..91be2b2ae1 100644
--- a/src/USER-REAXC/fix_qeq_reax.cpp
+++ b/src/USER-REAXC/fix_qeq_reax.cpp
@@ -40,6 +40,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define EV_TO_KCAL_PER_MOL 14.4
 #define SAFE_ZONE       1.2
diff --git a/src/USER-REAXC/fix_reax_c.cpp b/src/USER-REAXC/fix_reax_c.cpp
index f979bef1e0..8ec7165ffd 100644
--- a/src/USER-REAXC/fix_reax_c.cpp
+++ b/src/USER-REAXC/fix_reax_c.cpp
@@ -28,6 +28,7 @@
 #include "memory.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAX_REAX_BONDS      30
 #define MIN_REAX_BONDS      15
diff --git a/src/USER-REAXC/fix_reaxc_bonds.cpp b/src/USER-REAXC/fix_reaxc_bonds.cpp
index 2914232851..ced11b3530 100644
--- a/src/USER-REAXC/fix_reaxc_bonds.cpp
+++ b/src/USER-REAXC/fix_reaxc_bonds.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-SPH/fix_meso.cpp b/src/USER-SPH/fix_meso.cpp
index cfab98164e..ffb69a8c80 100644
--- a/src/USER-SPH/fix_meso.cpp
+++ b/src/USER-SPH/fix_meso.cpp
@@ -31,6 +31,7 @@
 #include "pair.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/USER-SPH/fix_meso_stationary.cpp b/src/USER-SPH/fix_meso_stationary.cpp
index 793e8dd217..f12297f072 100644
--- a/src/USER-SPH/fix_meso_stationary.cpp
+++ b/src/USER-SPH/fix_meso_stationary.cpp
@@ -31,6 +31,7 @@
 #include "pair.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix.cpp b/src/fix.cpp
index dc4263b7d1..5f19d75dca 100644
--- a/src/fix.cpp
+++ b/src/fix.cpp
@@ -20,6 +20,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
@@ -67,28 +68,6 @@ Fix::Fix(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
 
   maxvatom = 0;
   vatom = NULL;
-
-  // mask settings - same as in modify.cpp
-
-  INITIAL_INTEGRATE = 1;
-  POST_INTEGRATE = 2;
-  PRE_EXCHANGE = 4;
-  PRE_NEIGHBOR = 8;
-  PRE_FORCE = 16;
-  POST_FORCE = 32;
-  FINAL_INTEGRATE = 64;
-  END_OF_STEP = 128;
-  THERMO_ENERGY = 256;
-  INITIAL_INTEGRATE_RESPA = 512;
-  POST_INTEGRATE_RESPA = 1024;
-  PRE_FORCE_RESPA = 2048;
-  POST_FORCE_RESPA = 4096;
-  FINAL_INTEGRATE_RESPA = 8192;
-  MIN_PRE_EXCHANGE = 16384;
-  MIN_PRE_FORCE = 32768;
-  MIN_POST_FORCE = 65536;
-  MIN_ENERGY = 131072;
-  POST_RUN = 262144;
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/fix.h b/src/fix.h
index f7e9e39d75..56f36be3d0 100644
--- a/src/fix.h
+++ b/src/fix.h
@@ -76,14 +76,6 @@ class Fix : protected Pointers {
   double virial[6];              // accumlated virial
   double **vatom;                // accumulated per-atom virial
 
-  int INITIAL_INTEGRATE,POST_INTEGRATE;    // mask settings
-  int PRE_EXCHANGE,PRE_NEIGHBOR;
-  int PRE_FORCE,POST_FORCE,FINAL_INTEGRATE,END_OF_STEP,THERMO_ENERGY;
-  int INITIAL_INTEGRATE_RESPA,POST_INTEGRATE_RESPA;
-  int PRE_FORCE_RESPA,POST_FORCE_RESPA,FINAL_INTEGRATE_RESPA;
-  int MIN_PRE_EXCHANGE,MIN_PRE_FORCE,MIN_POST_FORCE,MIN_ENERGY;
-  int POST_RUN;
-
   Fix(class LAMMPS *, int, char **);
   virtual ~Fix();
   void modify_params(int, char **);
@@ -167,6 +159,29 @@ class Fix : protected Pointers {
   void v_tally(int, int *, double, double *);
 };
 
+namespace FixConst {
+  static const int INITIAL_INTEGRATE =       1<<0;
+  static const int POST_INTEGRATE =          1<<1;
+  static const int PRE_EXCHANGE =            1<<2;
+  static const int PRE_NEIGHBOR =            1<<3;
+  static const int PRE_FORCE =               1<<4;
+  static const int POST_FORCE =              1<<5;
+  static const int FINAL_INTEGRATE =         1<<6;
+  static const int END_OF_STEP =             1<<7;
+  static const int THERMO_ENERGY =           1<<8;
+  static const int INITIAL_INTEGRATE_RESPA = 1<<9;
+  static const int POST_INTEGRATE_RESPA =    1<<10;
+  static const int PRE_FORCE_RESPA =         1<<11;
+  static const int POST_FORCE_RESPA =        1<<12;
+  static const int FINAL_INTEGRATE_RESPA =   1<<13;
+  static const int MIN_PRE_EXCHANGE =        1<<14;
+  static const int MIN_PRE_FORCE =           1<<15;
+  static const int MIN_POST_FORCE =          1<<16;
+  static const int MIN_ENERGY =              1<<17;
+  static const int POST_RUN =                1<<18;
+  static const int FIX_CONST_LAST =          1<<19;
+}
+  
 }
 
 #endif
diff --git a/src/fix_adapt.cpp b/src/fix_adapt.cpp
index 59af597bc3..380eb8c8e5 100644
--- a/src/fix_adapt.cpp
+++ b/src/fix_adapt.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{PAIR,KSPACE,ATOM};
diff --git a/src/fix_addforce.cpp b/src/fix_addforce.cpp
index fee57525d8..03953b5a81 100644
--- a/src/fix_addforce.cpp
+++ b/src/fix_addforce.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,CONSTANT,EQUAL,ATOM};
 
diff --git a/src/fix_ave_atom.cpp b/src/fix_ave_atom.cpp
index 01f21f9508..b698ee24b2 100644
--- a/src/fix_ave_atom.cpp
+++ b/src/fix_ave_atom.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{X,V,F,COMPUTE,FIX,VARIABLE};
 
diff --git a/src/fix_ave_correlate.cpp b/src/fix_ave_correlate.cpp
index b84fc06b4d..6956965092 100644
--- a/src/fix_ave_correlate.cpp
+++ b/src/fix_ave_correlate.cpp
@@ -30,6 +30,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{COMPUTE,FIX,VARIABLE};
 enum{ONE,RUNNING};
diff --git a/src/fix_ave_histo.cpp b/src/fix_ave_histo.cpp
index e8b499ccd4..22ce073534 100644
--- a/src/fix_ave_histo.cpp
+++ b/src/fix_ave_histo.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{X,V,F,COMPUTE,FIX,VARIABLE};
 enum{ONE,RUNNING};
diff --git a/src/fix_ave_spatial.cpp b/src/fix_ave_spatial.cpp
index 18303b6cfe..ea541fb5f3 100644
--- a/src/fix_ave_spatial.cpp
+++ b/src/fix_ave_spatial.cpp
@@ -33,6 +33,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{LOWER,CENTER,UPPER,COORD};
 enum{V,F,DENSITY_NUMBER,DENSITY_MASS,COMPUTE,FIX,VARIABLE};
diff --git a/src/fix_ave_time.cpp b/src/fix_ave_time.cpp
index 3d4eb57d07..3dea04e518 100644
--- a/src/fix_ave_time.cpp
+++ b/src/fix_ave_time.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{COMPUTE,FIX,VARIABLE};
 enum{ONE,RUNNING,WINDOW};
diff --git a/src/fix_aveforce.cpp b/src/fix_aveforce.cpp
index c825e51b38..274820a0e3 100644
--- a/src/fix_aveforce.cpp
+++ b/src/fix_aveforce.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,CONSTANT,EQUAL};
 
diff --git a/src/fix_box_relax.cpp b/src/fix_box_relax.cpp
index f2b045b511..15bb264be1 100644
--- a/src/fix_box_relax.cpp
+++ b/src/fix_box_relax.cpp
@@ -31,6 +31,7 @@
 #include "math_extra.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,XYZ,XY,YZ,XZ};
 enum{ISO,ANISO,TRICLINIC};
diff --git a/src/fix_deform.cpp b/src/fix_deform.cpp
index 097683ad23..6e2d9fb6e6 100644
--- a/src/fix_deform.cpp
+++ b/src/fix_deform.cpp
@@ -32,6 +32,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{NONE,FINAL,DELTA,SCALE,VEL,ERATE,TRATE,VOLUME,WIGGLE};
diff --git a/src/fix_deposit.cpp b/src/fix_deposit.cpp
index 8bc15c34ba..b3f403a8d4 100644
--- a/src/fix_deposit.cpp
+++ b/src/fix_deposit.cpp
@@ -30,6 +30,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_drag.cpp b/src/fix_drag.cpp
index 51e744aada..30c886ae71 100644
--- a/src/fix_drag.cpp
+++ b/src/fix_drag.cpp
@@ -22,6 +22,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_dt_reset.cpp b/src/fix_dt_reset.cpp
index c35903a69b..1e60535fcc 100644
--- a/src/fix_dt_reset.cpp
+++ b/src/fix_dt_reset.cpp
@@ -30,6 +30,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define BIG 1.0e20
 
diff --git a/src/fix_efield.cpp b/src/fix_efield.cpp
index 42bc2efc94..2d6585b5ce 100644
--- a/src/fix_efield.cpp
+++ b/src/fix_efield.cpp
@@ -30,6 +30,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{CONSTANT,EQUAL,ATOM};
 
diff --git a/src/fix_enforce2d.cpp b/src/fix_enforce2d.cpp
index ad7ef9f615..d6f02b0188 100644
--- a/src/fix_enforce2d.cpp
+++ b/src/fix_enforce2d.cpp
@@ -20,6 +20,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_evaporate.cpp b/src/fix_evaporate.cpp
index e00d0ca9e3..eee0418b84 100644
--- a/src/fix_evaporate.cpp
+++ b/src/fix_evaporate.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_external.cpp b/src/fix_external.cpp
index dd92847cf0..63647b7a93 100644
--- a/src/fix_external.cpp
+++ b/src/fix_external.cpp
@@ -20,6 +20,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_gravity.cpp b/src/fix_gravity.cpp
index de71e6bd79..153ed9445d 100644
--- a/src/fix_gravity.cpp
+++ b/src/fix_gravity.cpp
@@ -24,6 +24,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{CHUTE,SPHERICAL,GRADIENT,VECTOR};
diff --git a/src/fix_heat.cpp b/src/fix_heat.cpp
index 45bd030cc2..645390180c 100644
--- a/src/fix_heat.cpp
+++ b/src/fix_heat.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_indent.cpp b/src/fix_indent.cpp
index 48f72ac048..642605bf6b 100644
--- a/src/fix_indent.cpp
+++ b/src/fix_indent.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,SPHERE,CYLINDER,PLANE};
 enum{INSIDE,OUTSIDE};
diff --git a/src/fix_langevin.cpp b/src/fix_langevin.cpp
index 4ee547dd89..60d18a5106 100644
--- a/src/fix_langevin.cpp
+++ b/src/fix_langevin.cpp
@@ -39,6 +39,7 @@
 #include "group.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 enum{CONSTANT,EQUAL,ATOM};
diff --git a/src/fix_lineforce.cpp b/src/fix_lineforce.cpp
index f56c28146a..5da729f84f 100644
--- a/src/fix_lineforce.cpp
+++ b/src/fix_lineforce.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_minimize.cpp b/src/fix_minimize.cpp
index e90aea1468..c0c61098d5 100644
--- a/src/fix_minimize.cpp
+++ b/src/fix_minimize.cpp
@@ -19,6 +19,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_momentum.cpp b/src/fix_momentum.cpp
index 8fb7f3ae02..a2067a516d 100644
--- a/src/fix_momentum.cpp
+++ b/src/fix_momentum.cpp
@@ -20,6 +20,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ----------------------------------------------------------------------
    Contributing author: Naveen Michaud-Agrawal (Johns Hopkins U)
diff --git a/src/fix_move.cpp b/src/fix_move.cpp
index 74657fa86e..060eb61ae6 100644
--- a/src/fix_move.cpp
+++ b/src/fix_move.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{LINEAR,WIGGLE,ROTATE,VARIABLE};
diff --git a/src/fix_nh.cpp b/src/fix_nh.cpp
index 1aa2ad87fb..9ead1ad403 100644
--- a/src/fix_nh.cpp
+++ b/src/fix_nh.cpp
@@ -35,6 +35,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define DELTAFLIP 0.1
 #define TILTMAX 1.5
diff --git a/src/fix_nh_sphere.cpp b/src/fix_nh_sphere.cpp
index 7bdbcee266..5380508097 100644
--- a/src/fix_nh_sphere.cpp
+++ b/src/fix_nh_sphere.cpp
@@ -23,6 +23,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define INERTIA 0.4          // moment of inertia prefactor for sphere
 
diff --git a/src/fix_nph.cpp b/src/fix_nph.cpp
index e65da36589..b9e0f9e223 100644
--- a/src/fix_nph.cpp
+++ b/src/fix_nph.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nph_sphere.cpp b/src/fix_nph_sphere.cpp
index 550dd8f5bc..cdc7801cf5 100644
--- a/src/fix_nph_sphere.cpp
+++ b/src/fix_nph_sphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_npt.cpp b/src/fix_npt.cpp
index 84522560ac..a412bc9c6f 100644
--- a/src/fix_npt.cpp
+++ b/src/fix_npt.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_npt_sphere.cpp b/src/fix_npt_sphere.cpp
index b58971f550..4fafcccbb5 100644
--- a/src/fix_npt_sphere.cpp
+++ b/src/fix_npt_sphere.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nve.cpp b/src/fix_nve.cpp
index ce4e253069..cf4044ab07 100644
--- a/src/fix_nve.cpp
+++ b/src/fix_nve.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nve_limit.cpp b/src/fix_nve_limit.cpp
index a5e2b28946..8a47113f3c 100644
--- a/src/fix_nve_limit.cpp
+++ b/src/fix_nve_limit.cpp
@@ -23,6 +23,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nve_noforce.cpp b/src/fix_nve_noforce.cpp
index b4d67be752..ffffd01235 100644
--- a/src/fix_nve_noforce.cpp
+++ b/src/fix_nve_noforce.cpp
@@ -20,6 +20,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nve_sphere.cpp b/src/fix_nve_sphere.cpp
index a00fa0bdf1..a3d270155f 100644
--- a/src/fix_nve_sphere.cpp
+++ b/src/fix_nve_sphere.cpp
@@ -23,6 +23,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define INERTIA 0.4          // moment of inertia prefactor for sphere
 
diff --git a/src/fix_nvt.cpp b/src/fix_nvt.cpp
index 60478e6c41..c7d7f054e8 100644
--- a/src/fix_nvt.cpp
+++ b/src/fix_nvt.cpp
@@ -18,6 +18,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_nvt_sllod.cpp b/src/fix_nvt_sllod.cpp
index ab5c876ad3..a18787f177 100644
--- a/src/fix_nvt_sllod.cpp
+++ b/src/fix_nvt_sllod.cpp
@@ -29,6 +29,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NO_REMAP,X_REMAP,V_REMAP};                   // same as fix_deform.cpp
 
diff --git a/src/fix_nvt_sphere.cpp b/src/fix_nvt_sphere.cpp
index 84c4a6bbc6..b90fc23ffc 100644
--- a/src/fix_nvt_sphere.cpp
+++ b/src/fix_nvt_sphere.cpp
@@ -18,6 +18,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_orient_fcc.cpp b/src/fix_orient_fcc.cpp
index 109373add7..e9f4c8fbde 100644
--- a/src/fix_orient_fcc.cpp
+++ b/src/fix_orient_fcc.cpp
@@ -33,6 +33,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 #define BIG 1000000000
diff --git a/src/fix_planeforce.cpp b/src/fix_planeforce.cpp
index 5b7a0cfbec..43fe933c1c 100644
--- a/src/fix_planeforce.cpp
+++ b/src/fix_planeforce.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_press_berendsen.cpp b/src/fix_press_berendsen.cpp
index 36abc158b2..8238e3a617 100644
--- a/src/fix_press_berendsen.cpp
+++ b/src/fix_press_berendsen.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 enum{NONE,XYZ,XY,YZ,XZ};
diff --git a/src/fix_print.cpp b/src/fix_print.cpp
index c38945a8c0..7d2d5116a3 100644
--- a/src/fix_print.cpp
+++ b/src/fix_print.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAXLINE 1024
 
diff --git a/src/fix_read_restart.cpp b/src/fix_read_restart.cpp
index b3d850ac4f..e4d29a0a3b 100644
--- a/src/fix_read_restart.cpp
+++ b/src/fix_read_restart.cpp
@@ -17,6 +17,7 @@
 #include "memory.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_recenter.cpp b/src/fix_recenter.cpp
index ac752b99c3..a93c1b7893 100644
--- a/src/fix_recenter.cpp
+++ b/src/fix_recenter.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{BOX,LATTICE,FRACTION};
 
diff --git a/src/fix_respa.cpp b/src/fix_respa.cpp
index 37eda1e4da..f2fd4d1756 100644
--- a/src/fix_respa.cpp
+++ b/src/fix_respa.cpp
@@ -18,6 +18,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_restrain.cpp b/src/fix_restrain.cpp
index f3048cc18d..723f156282 100644
--- a/src/fix_restrain.cpp
+++ b/src/fix_restrain.cpp
@@ -31,6 +31,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 enum{DIHEDRAL};
diff --git a/src/fix_rigid.cpp b/src/fix_rigid.cpp
index 63df87b782..2ff57ae4bd 100644
--- a/src/fix_rigid.cpp
+++ b/src/fix_rigid.cpp
@@ -35,6 +35,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 #define TOLERANCE 1.0e-6
diff --git a/src/fix_rigid_nve.cpp b/src/fix_rigid_nve.cpp
index 3b539f2533..39af01b2f5 100644
--- a/src/fix_rigid_nve.cpp
+++ b/src/fix_rigid_nve.cpp
@@ -34,6 +34,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_rigid_nvt.cpp b/src/fix_rigid_nvt.cpp
index 824f8b4bbf..a6f1d07e03 100644
--- a/src/fix_rigid_nvt.cpp
+++ b/src/fix_rigid_nvt.cpp
@@ -35,6 +35,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_setforce.cpp b/src/fix_setforce.cpp
index c7dba74f59..78f438fff3 100644
--- a/src/fix_setforce.cpp
+++ b/src/fix_setforce.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NONE,CONSTANT,EQUAL,ATOM};
 
diff --git a/src/fix_shake.cpp b/src/fix_shake.cpp
index 5cdce3ad25..db40a67da6 100644
--- a/src/fix_shake.cpp
+++ b/src/fix_shake.cpp
@@ -35,6 +35,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 using namespace MathConst;
 
 #define BIG 1.0e20
diff --git a/src/fix_shear_history.cpp b/src/fix_shear_history.cpp
index 4e284c7f65..b1ef95806f 100644
--- a/src/fix_shear_history.cpp
+++ b/src/fix_shear_history.cpp
@@ -25,6 +25,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAXTOUCH 15
 
diff --git a/src/fix_spring.cpp b/src/fix_spring.cpp
index f3ac3e378b..28a5b74a5e 100644
--- a/src/fix_spring.cpp
+++ b/src/fix_spring.cpp
@@ -27,6 +27,7 @@
 #include "group.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define SMALL 1.0e-10
 
diff --git a/src/fix_spring_rg.cpp b/src/fix_spring_rg.cpp
index 4723c8fdb9..c9c6322c6f 100644
--- a/src/fix_spring_rg.cpp
+++ b/src/fix_spring_rg.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_spring_self.cpp b/src/fix_spring_self.cpp
index 4be64ed271..0b5378d4fe 100644
--- a/src/fix_spring_self.cpp
+++ b/src/fix_spring_self.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_store_force.cpp b/src/fix_store_force.cpp
index 98c5f918f8..20a0ea412c 100644
--- a/src/fix_store_force.cpp
+++ b/src/fix_store_force.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_store_state.cpp b/src/fix_store_state.cpp
index d98c76912f..a5610adc8b 100644
--- a/src/fix_store_state.cpp
+++ b/src/fix_store_state.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{KEYWORD,COMPUTE,FIX,VARIABLE};
 
diff --git a/src/fix_temp_berendsen.cpp b/src/fix_temp_berendsen.cpp
index bed8d8bb68..9182b42388 100644
--- a/src/fix_temp_berendsen.cpp
+++ b/src/fix_temp_berendsen.cpp
@@ -25,6 +25,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 
diff --git a/src/fix_temp_rescale.cpp b/src/fix_temp_rescale.cpp
index d0d67368bc..0eb2a965d6 100644
--- a/src/fix_temp_rescale.cpp
+++ b/src/fix_temp_rescale.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{NOBIAS,BIAS};
 
diff --git a/src/fix_thermal_conductivity.cpp b/src/fix_thermal_conductivity.cpp
index cf901c9a83..e3ec944e6d 100644
--- a/src/fix_thermal_conductivity.cpp
+++ b/src/fix_thermal_conductivity.cpp
@@ -28,6 +28,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define BIG 1.0e10
 
diff --git a/src/fix_tmd.cpp b/src/fix_tmd.cpp
index 1ef84c326c..5627802b7c 100644
--- a/src/fix_tmd.cpp
+++ b/src/fix_tmd.cpp
@@ -33,6 +33,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define CHUNK 1000
 #define MAXLINE 256
diff --git a/src/fix_ttm.cpp b/src/fix_ttm.cpp
index 4bc35c5097..8f5eecfc7a 100644
--- a/src/fix_ttm.cpp
+++ b/src/fix_ttm.cpp
@@ -34,6 +34,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define MAXLINE 1024
 
diff --git a/src/fix_viscosity.cpp b/src/fix_viscosity.cpp
index 04bcd3394c..e566a5057e 100644
--- a/src/fix_viscosity.cpp
+++ b/src/fix_viscosity.cpp
@@ -27,6 +27,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 // needs to be big, but not so big that lose precision when subtract velocity
 
diff --git a/src/fix_viscous.cpp b/src/fix_viscous.cpp
index 5345268bb4..f54140db02 100644
--- a/src/fix_viscous.cpp
+++ b/src/fix_viscous.cpp
@@ -21,6 +21,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_wall.cpp b/src/fix_wall.cpp
index 5ab1a49e31..b9e924c9cf 100644
--- a/src/fix_wall.cpp
+++ b/src/fix_wall.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{XLO=0,XHI=1,YLO=2,YHI=3,ZLO=4,ZHI=5};
 enum{NONE=0,EDGE,CONSTANT,VARIABLE};
diff --git a/src/fix_wall_harmonic.cpp b/src/fix_wall_harmonic.cpp
index e7eb85b54c..48a32331b5 100644
--- a/src/fix_wall_harmonic.cpp
+++ b/src/fix_wall_harmonic.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_wall_lj126.cpp b/src/fix_wall_lj126.cpp
index 47b0eba6f3..4aa87e07cc 100644
--- a/src/fix_wall_lj126.cpp
+++ b/src/fix_wall_lj126.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_wall_lj93.cpp b/src/fix_wall_lj93.cpp
index 0f8f9dff19..d2f92825e8 100644
--- a/src/fix_wall_lj93.cpp
+++ b/src/fix_wall_lj93.cpp
@@ -17,6 +17,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/fix_wall_reflect.cpp b/src/fix_wall_reflect.cpp
index f16b23e016..f6538300e6 100644
--- a/src/fix_wall_reflect.cpp
+++ b/src/fix_wall_reflect.cpp
@@ -25,6 +25,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{XLO=0,XHI=1,YLO=2,YHI=3,ZLO=4,ZHI=5};
 enum{NONE=0,EDGE,CONSTANT,VARIABLE};
diff --git a/src/fix_wall_region.cpp b/src/fix_wall_region.cpp
index 151e20259d..bd5b3ea98b 100644
--- a/src/fix_wall_region.cpp
+++ b/src/fix_wall_region.cpp
@@ -26,6 +26,7 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 enum{LJ93,LJ126,COLLOID,HARMONIC};
 
diff --git a/src/modify.cpp b/src/modify.cpp
index aeafe61d57..09f3a3ce29 100644
--- a/src/modify.cpp
+++ b/src/modify.cpp
@@ -28,30 +28,10 @@
 #include "error.h"
 
 using namespace LAMMPS_NS;
+using namespace FixConst;
 
 #define DELTA 4
 
-// mask settings - same as in fix.cpp
-
-#define INITIAL_INTEGRATE   1
-#define POST_INTEGRATE      2
-#define PRE_EXCHANGE        4
-#define PRE_NEIGHBOR        8
-#define PRE_FORCE          16
-#define POST_FORCE         32
-#define FINAL_INTEGRATE    64
-#define END_OF_STEP       128
-#define THERMO_ENERGY     256
-#define INITIAL_INTEGRATE_RESPA   512
-#define POST_INTEGRATE_RESPA     1024
-#define PRE_FORCE_RESPA          2048
-#define POST_FORCE_RESPA         4096
-#define FINAL_INTEGRATE_RESPA    8192
-#define MIN_PRE_EXCHANGE        16384
-#define MIN_PRE_FORCE           32768
-#define MIN_POST_FORCE          65536
-#define MIN_ENERGY             131072
-#define POST_RUN               262144
 
 #define BIG 1.0e20