diff --git a/src/USER-EFF/compute_ke_atom_eff.cpp b/src/USER-EFF/compute_ke_atom_eff.cpp
index 73e63313af..20d866c5a0 100644
--- a/src/USER-EFF/compute_ke_atom_eff.cpp
+++ b/src/USER-EFF/compute_ke_atom_eff.cpp
@@ -15,6 +15,7 @@
    Contributing author: Andres Jaramillo-Botero
 ------------------------------------------------------------------------- */
 
+#include "math.h"
 #include "string.h"
 #include "compute_ke_atom_eff.h"
 #include "atom.h"
@@ -96,7 +97,7 @@ void ComputeKEAtomEff::compute_peratom()
       if (mask[i] & groupbit) {
         ke[i] = 0.5 * mvv2e * mass[type[i]] * 
           (v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2]);
-        if (abs(spin[i])==1)
+        if (fabs(spin[i])==1)
           ke[i] += 0.5 * mvv2e * mass[type[i]] * ervel[i]*ervel[i] * 0.75;
       } else ke[i] = 0.0;
     }
diff --git a/src/USER-EFF/compute_ke_eff.cpp b/src/USER-EFF/compute_ke_eff.cpp
index 08759c7379..15ee955fdb 100644
--- a/src/USER-EFF/compute_ke_eff.cpp
+++ b/src/USER-EFF/compute_ke_eff.cpp
@@ -16,6 +16,7 @@
 ------------------------------------------------------------------------- */
 
 #include "mpi.h"
+#include "math.h"
 #include "compute_ke_eff.h"
 #include "atom.h"
 #include "update.h"
@@ -70,7 +71,7 @@ double ComputeKEEff::compute_scalar()
       if (mask[i] & groupbit) {
         ke += mass[type[i]]*(v[i][0]*v[i][0] + v[i][1]*v[i][1] + 
                              v[i][2]*v[i][2]);
-        if (abs(spin[i])==1) ke += 0.75*mass[type[i]]*ervel[i]*ervel[i];
+        if (fabs(spin[i])==1) ke += 0.75*mass[type[i]]*ervel[i]*ervel[i];
       }
   }
 
diff --git a/src/USER-EFF/compute_temp_deform_eff.cpp b/src/USER-EFF/compute_temp_deform_eff.cpp
index 5a093b65e0..5001e03773 100644
--- a/src/USER-EFF/compute_temp_deform_eff.cpp
+++ b/src/USER-EFF/compute_temp_deform_eff.cpp
@@ -16,8 +16,9 @@
 ------------------------------------------------------------------------- */
 
 #include "mpi.h"
-#include "compute_temp_deform_eff.h"
+#include "math.h"
 #include "string.h"
+#include "compute_temp_deform_eff.h"
 #include "domain.h"
 #include "atom.h"
 #include "update.h"
@@ -107,7 +108,7 @@ void ComputeTempDeformEff::dof_compute()
   int one = 0;
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit) {
-      if (abs(spin[i])==1) one++;
+      if (fabs(spin[i]) == 1) one++;
     }
   int nelectrons;
   MPI_Allreduce(&one,&nelectrons,1,MPI_INT,MPI_SUM,world);
@@ -158,7 +159,7 @@ double ComputeTempDeformEff::compute_scalar()
       if (mass) {
         t += (vthermal[0]*vthermal[0] + vthermal[1]*vthermal[1] + 
               vthermal[2]*vthermal[2])* mass[type[i]];
-        if (abs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
+        if (fabs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
       }
     }
   
@@ -209,7 +210,7 @@ void ComputeTempDeformEff::compute_vector()
       t[3] += massone * vthermal[0]*vthermal[1];
       t[4] += massone * vthermal[0]*vthermal[2];
       t[5] += massone * vthermal[1]*vthermal[2];
-      if (abs(spin[i])==1) {
+      if (fabs(spin[i])==1) {
         t[0] += 0.75 * massone * ervel[i]*ervel[i];
         t[1] += 0.75 * massone * ervel[i]*ervel[i];
         t[2] += 0.75 * massone * ervel[i]*ervel[i];
diff --git a/src/USER-EFF/compute_temp_eff.cpp b/src/USER-EFF/compute_temp_eff.cpp
index d5e359b942..29f9315995 100644
--- a/src/USER-EFF/compute_temp_eff.cpp
+++ b/src/USER-EFF/compute_temp_eff.cpp
@@ -16,6 +16,7 @@
 ------------------------------------------------------------------------- */
 
 #include "mpi.h"
+#include "math.h"
 #include "string.h"
 #include "compute_temp_eff.h"
 #include "atom.h"
@@ -80,7 +81,7 @@ void ComputeTempEff::dof_compute()
   int one = 0;
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit) {
-      if (abs(spin[i])==1) one++;
+      if (fabs(spin[i])==1) one++;
     }
   int nelectrons;
   MPI_Allreduce(&one,&nelectrons,1,MPI_INT,MPI_SUM,world);
@@ -114,7 +115,7 @@ double ComputeTempEff::compute_scalar()
       if (mask[i] & groupbit) {
         t += (v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2]) * 
           mass[type[i]];
-        if (abs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
+        if (fabs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
       }
     }
   }
@@ -153,7 +154,7 @@ void ComputeTempEff::compute_vector()
       t[3] += massone * v[i][0]*v[i][1];
       t[4] += massone * v[i][0]*v[i][2];
       t[5] += massone * v[i][1]*v[i][2];
-      if (abs(spin[i])==1) {
+      if (fabs(spin[i])==1) {
         t[0] += 0.75*massone*ervel[i]*ervel[i];
         t[1] += 0.75*massone*ervel[i]*ervel[i];
         t[2] += 0.75*massone*ervel[i]*ervel[i];
diff --git a/src/USER-EFF/compute_temp_region_eff.cpp b/src/USER-EFF/compute_temp_region_eff.cpp
index 7af81a42c7..58af7098be 100644
--- a/src/USER-EFF/compute_temp_region_eff.cpp
+++ b/src/USER-EFF/compute_temp_region_eff.cpp
@@ -16,6 +16,7 @@
 ------------------------------------------------------------------------- */
 
 #include "mpi.h"
+#include "math.h"
 #include "string.h"
 #include "compute_temp_region_eff.h"
 #include "atom.h"
@@ -114,7 +115,7 @@ double ComputeTempRegionEff::compute_scalar()
         count++;
         t += (v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2]) * 
           mass[type[i]];
-        if (abs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
+        if (fabs(spin[i])==1) t += 0.75*mass[type[i]]*ervel[i]*ervel[i];
       }
   }
 
@@ -127,7 +128,7 @@ double ComputeTempRegionEff::compute_scalar()
   int one = 0;
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit && region->match(x[i][0],x[i][1],x[i][2])) {
-      if (abs(spin[i])==1) one++;
+      if (fabs(spin[i])==1) one++;
     }
   int nelectrons_region;
   MPI_Allreduce(&one,&nelectrons_region,1,MPI_INT,MPI_SUM,world);
@@ -173,7 +174,7 @@ void ComputeTempRegionEff::compute_vector()
       t[4] += massone * v[i][0]*v[i][2];
       t[5] += massone * v[i][1]*v[i][2];
                 
-      if (abs(spin[i])==1) {
+      if (fabs(spin[i])==1) {
         t[0] += 0.75 * massone * ervel[i]*ervel[i];
         t[1] += 0.75 * massone * ervel[i]*ervel[i];
         t[2] += 0.75 * massone * ervel[i]*ervel[i];
diff --git a/src/USER-EFF/fix_nh_eff.cpp b/src/USER-EFF/fix_nh_eff.cpp
index 9dafafb247..61a6ea506e 100644
--- a/src/USER-EFF/fix_nh_eff.cpp
+++ b/src/USER-EFF/fix_nh_eff.cpp
@@ -60,7 +60,7 @@ void FixNHEff::nve_v()
 
   for (int i = 0; i < nlocal; i++) {    
     if (mask[i] & groupbit) {
-      if (abs(spin[i])==1) {
+      if (fabs(spin[i])==1) {
 	dtfm = dtf / mass[type[i]];
 	ervel[i] = dtfm * erforce[i] / 0.75;
       }
@@ -87,7 +87,7 @@ void FixNHEff::nve_x()
 
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit)
-      if (abs(spin[i])==1) eradius[i] += dtv * ervel[i];
+      if (fabs(spin[i])==1) eradius[i] += dtv * ervel[i];
 }
 
 /* ----------------------------------------------------------------------
@@ -108,5 +108,5 @@ void FixNHEff::nh_v_temp()
 
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit)
-      if (abs(spin[i])==1) ervel[i] *= factor_eta;
+      if (fabs(spin[i])==1) ervel[i] *= factor_eta;
 }
diff --git a/src/USER-EFF/fix_nve_eff.cpp b/src/USER-EFF/fix_nve_eff.cpp
index 99866afe03..048b251f9c 100644
--- a/src/USER-EFF/fix_nve_eff.cpp
+++ b/src/USER-EFF/fix_nve_eff.cpp
@@ -15,6 +15,7 @@
    Contributing author: Andres Jaramillo-Botero (Caltech)
 ------------------------------------------------------------------------- */
 
+#include "math.h"
 #include "stdio.h"
 #include "string.h"
 #include "fix_nve_eff.h"
@@ -98,7 +99,7 @@ void FixNVEEff::initial_integrate(int vflag)
         x[i][0] += dtv * v[i][0];
         x[i][1] += dtv * v[i][1];
         x[i][2] += dtv * v[i][2];
-        if (abs(spin[i])==1) {
+        if (fabs(spin[i])==1) {
           ervel[i] += dtfm * erforce[i] / 0.75;
           eradius[i] += dtv * ervel[i];
         }
@@ -133,7 +134,7 @@ void FixNVEEff::final_integrate()
         v[i][0] += dtfm * f[i][0];
         v[i][1] += dtfm * f[i][1];
         v[i][2] += dtfm * f[i][2];
-        if (abs(spin[i])==1)
+        if (fabs(spin[i])==1)
           ervel[i] += dtfm * erforce[i] / 0.75;
       }
     }
diff --git a/src/USER-EFF/fix_nvt_sllod_eff.cpp b/src/USER-EFF/fix_nvt_sllod_eff.cpp
index 12bdac820f..435d70c20c 100644
--- a/src/USER-EFF/fix_nvt_sllod_eff.cpp
+++ b/src/USER-EFF/fix_nvt_sllod_eff.cpp
@@ -121,7 +121,7 @@ void FixNVTSllodEff::nh_v_temp()
       v[i][1] = v[i][1]*factor_eta - dthalf*vdelu[1];
       v[i][2] = v[i][2]*factor_eta - dthalf*vdelu[2];
       temperature->restore_bias(i,v[i]);
-      if (abs(spin[i])==1)
+      if (fabs(spin[i])==1)
         ervel[i] = ervel[i]*factor_eta -
           dthalf*sqrt(pow(vdelu[0],2)+pow(vdelu[1],2)+pow(vdelu[2],2));
     }