diff --git a/src/USER-DPD/nbin_ssa.h b/src/USER-DPD/nbin_ssa.h
index 2a0175081..12a572b94 100644
--- a/src/USER-DPD/nbin_ssa.h
+++ b/src/USER-DPD/nbin_ssa.h
@@ -1,167 +1,104 @@
 /* -*- c++ -*- ----------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    http://lammps.sandia.gov, Sandia National Laboratories
    Steve Plimpton, sjplimp@sandia.gov
 
    Copyright (2003) Sandia Corporation.  Under the terms of Contract
    DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
    certain rights in this software.  This software is distributed under
    the GNU General Public License.
 
    See the README file in the top-level LAMMPS directory.
 ------------------------------------------------------------------------- */
 
 #ifdef NBIN_CLASS
 
 NBinStyle(ssa,
           NBinSSA,
           NB_SSA)
 
 #else
 
 #ifndef LMP_NBIN_SSA_H
 #define LMP_NBIN_SSA_H
 
 #include "nbin_standard.h"
+#include "math.h"
+#include "error.h"
 
 namespace LAMMPS_NS {
 
 class NBinSSA : public NBinStandard {
  public:
 
   int gairhead_ssa[8];       // index of 1st ghost atom in each AIR
 
   // Bounds of the local atoms in the binhead array
   int lbinxlo;               // lowest local bin x-dim coordinate
   int lbinylo;               // lowest local bin y-dim coordinate
   int lbinzlo;               // lowest local bin z-dim coordinate
   int lbinxhi;               // highest local bin x-dim coordinate
   int lbinyhi;               // highest local bin y-dim coordinate
   int lbinzhi;               // highest local bin z-dim coordinate
 
   NBinSSA(class LAMMPS *);
   ~NBinSSA();
 
   void bin_atoms_setup(int);
   void bin_atoms();
 
   bigint memory_usage();
 
-  inline
-  int coord2bin(const double & x,const double & y,const double & z) const
-  {
-    int ix,iy,iz;
-
-    if (x >= bboxhi_[0])
-      ix = static_cast<int> ((x-bboxhi_[0])*bininvx) + nbinx;
-    else if (x >= bboxlo_[0]) {
-      ix = static_cast<int> ((x-bboxlo_[0])*bininvx);
-      ix = MIN(ix,nbinx-1);
-    } else
-      ix = static_cast<int> ((x-bboxlo_[0])*bininvx) - 1;
-
-    if (y >= bboxhi_[1])
-      iy = static_cast<int> ((y-bboxhi_[1])*bininvy) + nbiny;
-    else if (y >= bboxlo_[1]) {
-      iy = static_cast<int> ((y-bboxlo_[1])*bininvy);
-      iy = MIN(iy,nbiny-1);
-    } else
-      iy = static_cast<int> ((y-bboxlo_[1])*bininvy) - 1;
-
-    if (z >= bboxhi_[2])
-      iz = static_cast<int> ((z-bboxhi_[2])*bininvz) + nbinz;
-    else if (z >= bboxlo_[2]) {
-      iz = static_cast<int> ((z-bboxlo_[2])*bininvz);
-      iz = MIN(iz,nbinz-1);
-    } else
-      iz = static_cast<int> ((z-bboxlo_[2])*bininvz) - 1;
-
-    return (iz-mbinzlo)*mbiny*mbinx + (iy-mbinylo)*mbinx + (ix-mbinxlo);
-  }
-
-  inline
-  int coord2bin(const double & x,const double & y,const double & z, int* i) const
-  {
-    int ix,iy,iz;
-
-    if (x >= bboxhi_[0])
-      ix = static_cast<int> ((x-bboxhi_[0])*bininvx) + nbinx;
-    else if (x >= bboxlo_[0]) {
-      ix = static_cast<int> ((x-bboxlo_[0])*bininvx);
-      ix = MIN(ix,nbinx-1);
-    } else
-      ix = static_cast<int> ((x-bboxlo_[0])*bininvx) - 1;
-
-    if (y >= bboxhi_[1])
-      iy = static_cast<int> ((y-bboxhi_[1])*bininvy) + nbiny;
-    else if (y >= bboxlo_[1]) {
-      iy = static_cast<int> ((y-bboxlo_[1])*bininvy);
-      iy = MIN(iy,nbiny-1);
-    } else
-      iy = static_cast<int> ((y-bboxlo_[1])*bininvy) - 1;
-
-    if (z >= bboxhi_[2])
-      iz = static_cast<int> ((z-bboxhi_[2])*bininvz) + nbinz;
-    else if (z >= bboxlo_[2]) {
-      iz = static_cast<int> ((z-bboxlo_[2])*bininvz);
-      iz = MIN(iz,nbinz-1);
-    } else
-      iz = static_cast<int> ((z-bboxlo_[2])*bininvz) - 1;
-
-    i[0] = ix - mbinxlo;
-    i[1] = iy - mbinylo;
-    i[2] = iz - mbinzlo;
-
-    return (iz-mbinzlo)*mbiny*mbinx + (iy-mbinylo)*mbinx + (ix-mbinxlo);
-  }
-
   inline
   int coord2bin(const double & x,const double & y,const double & z, int &ixo, int &iyo, int &izo) const
   {
     int ix,iy,iz;
 
+    if (!ISFINITE(x) || !ISFINITE(y) || !ISFINITE(z))
+      error->one(FLERR,"Non-numeric positions - simulation unstable");
+
     if (x >= bboxhi_[0])
       ix = static_cast<int> ((x-bboxhi_[0])*bininvx) + nbinx;
     else if (x >= bboxlo_[0]) {
       ix = static_cast<int> ((x-bboxlo_[0])*bininvx);
       ix = MIN(ix,nbinx-1);
     } else
       ix = static_cast<int> ((x-bboxlo_[0])*bininvx) - 1;
 
     if (y >= bboxhi_[1])
       iy = static_cast<int> ((y-bboxhi_[1])*bininvy) + nbiny;
     else if (y >= bboxlo_[1]) {
       iy = static_cast<int> ((y-bboxlo_[1])*bininvy);
       iy = MIN(iy,nbiny-1);
     } else
       iy = static_cast<int> ((y-bboxlo_[1])*bininvy) - 1;
 
     if (z >= bboxhi_[2])
       iz = static_cast<int> ((z-bboxhi_[2])*bininvz) + nbinz;
     else if (z >= bboxlo_[2]) {
       iz = static_cast<int> ((z-bboxlo_[2])*bininvz);
       iz = MIN(iz,nbinz-1);
     } else
       iz = static_cast<int> ((z-bboxlo_[2])*bininvz) - 1;
 
     ixo = ix - mbinxlo;
     iyo = iy - mbinylo;
     izo = iz - mbinzlo;
 
     return (iz-mbinzlo)*mbiny*mbinx + (iy-mbinylo)*mbinx + (ix-mbinxlo);
   }
 
  private:
   int coord2ssaAIR(const double *);  // map atom coord to an AIR number
   double bboxlo_[3],bboxhi_[3];
 
 };
 
 }
 
 #endif
 #endif
 
 /* ERROR/WARNING messages:
 
 */