diff --git a/doc/fix_gle.html b/doc/fix_gle.html
index e82902a973ffac95677b699062d87145424814d8..5ae0c8783d06ec3128f2e23aa801d9af159cb24f 100644
--- a/doc/fix_gle.html
+++ b/doc/fix_gle.html
@@ -50,7 +50,8 @@ vibrational modes in the system to inexpensive (approximate)
 modelling of nuclear quantum effects. Contrary to 
 <A HREF = "fix_langevin.html">fix langevin</A>, this fix performs both 
 thermostatting and evolution of the Hamiltonian equations of motion, so it 
-does not need to be used together with <A HREF = "fix_nve.html">fix nve</A>.
+should not be used together with <A HREF = "fix_nve.html">fix nve</A> -- at least not 
+on the same atom groups. 
 </P>
 <P>Each degree of freedom in the thermostatted group is supplemented
 with Ns additional degrees of freedom s, and the equations of motion
@@ -93,6 +94,14 @@ generate its own unique seed and its own stream of random numbers.
 Thus the dynamics of the system will not be identical on two runs on
 different numbers of processors. 
 </P>
+<P>Note also that the Generalized Langevin Dynamics scheme that is 
+implemented by the <A HREF = "fix_gld.html">fix gld</A> scheme is closely related
+to the present one. In fact, it should be always possible to cast the
+Prony series form of the memory kernel used by GLD into an appropriate
+input matrix for <A HREF = "fix_gle.html">fix_gle</A>. While the GLE scheme is more
+general, the form used by <A HREF = "fix_gld.html">fix gld</A> can be more directly
+related to the representation of an implicit solvent environment. 
+</P>
 <P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
 </P>
 <P>The instantaneous values of the extended variables are written to
@@ -127,6 +136,11 @@ with rigid bodies, SHAKE or RATTLE. It is expected that all the
 thermostatted degrees of freedom are fully flexible, and the sampled
 ensemble will not be correct otherwise.
 </P>
+<P>In order to perform constant-pressure simulations please use 
+<A HREF = "fix_press_berendsen.html">fix press/berendsen</A>, rather than 
+<A HREF = "fix_npt.html">fix_npt</A>, to avoid duplicate integration of the
+equations of motion. 
+</P>
 <P>This fix is part of the USER-MISC package.  It is only enabled if LAMMPS
 was built with that package.  See the <A HREF = "Section_start.html#start_3">Making
 LAMMPS</A> section for more info.
diff --git a/doc/fix_gle.txt b/doc/fix_gle.txt
index 08ff64777c14b5210a3d4aedcd6af97773f463c7..8ce2a2b6fd32b9f157fad6d71d855affc5d409a1 100644
--- a/doc/fix_gle.txt
+++ b/doc/fix_gle.txt
@@ -40,7 +40,8 @@ vibrational modes in the system to inexpensive (approximate)
 modelling of nuclear quantum effects. Contrary to 
 "fix langevin"_fix_langevin.html, this fix performs both 
 thermostatting and evolution of the Hamiltonian equations of motion, so it 
-does not need to be used together with "fix nve"_fix_nve.html.
+should not be used together with "fix nve"_fix_nve.html -- at least not 
+on the same atom groups. 
 
 Each degree of freedom in the thermostatted group is supplemented
 with Ns additional degrees of freedom s, and the equations of motion
@@ -83,6 +84,14 @@ generate its own unique seed and its own stream of random numbers.
 Thus the dynamics of the system will not be identical on two runs on
 different numbers of processors. 
 
+Note also that the Generalized Langevin Dynamics scheme that is 
+implemented by the "fix gld"_fix_gld.html scheme is closely related
+to the present one. In fact, it should be always possible to cast the
+Prony series form of the memory kernel used by GLD into an appropriate
+input matrix for "fix_gle"_fix_gle.html. While the GLE scheme is more
+general, the form used by "fix gld"_fix_gld.html can be more directly
+related to the representation of an implicit solvent environment. 
+
 [Restart, fix_modify, output, run start/stop, minimize info:]
 
 The instantaneous values of the extended variables are written to
@@ -117,6 +126,11 @@ with rigid bodies, SHAKE or RATTLE. It is expected that all the
 thermostatted degrees of freedom are fully flexible, and the sampled
 ensemble will not be correct otherwise.
 
+In order to perform constant-pressure simulations please use 
+"fix press/berendsen"_fix_press_berendsen.html, rather than 
+"fix_npt"_fix_npt.html, to avoid duplicate integration of the
+equations of motion. 
+
 This fix is part of the USER-MISC package.  It is only enabled if LAMMPS
 was built with that package.  See the "Making
 LAMMPS"_Section_start.html#start_3 section for more info.
diff --git a/src/USER-MISC/fix_gle.cpp b/src/USER-MISC/fix_gle.cpp
index 5f28dea37b7b4129608ba4ee354912e4c8d10ace..95f868f95f1f4eaf7f5e1eaf8f5698bb9266dbe5 100644
--- a/src/USER-MISC/fix_gle.cpp
+++ b/src/USER-MISC/fix_gle.cpp
@@ -82,7 +82,13 @@ void StabCholesky(int n, const double* MMt, double* M)
         for (k=0; k<i; ++k) D[i]-=L[midx(n,i,k)]*L[midx(n,i,k)]*D[k];
     }
 
-    for(i=0; i<n; ++i) D[i]=(D[i]>0.?sqrt(D[i]):0.);
+    for(i=0; i<n; ++i) 
+    {
+#ifdef GLE_DEBUG		
+		if (D[i]<0) fprintf(stderr,"GLE Cholesky: Negative diagonal term %le, has been set to zero.\n", D[i]);			
+#endif		
+		D[i]=(D[i]>0.?sqrt(D[i]):0.);
+	}
 
     for(i=0; i<n; ++i) for (j=0; j<n; j++) M[midx(n,i,j)]=L[midx(n,i,j)]*D[j];
 }
diff --git a/src/USER-MISC/fix_ipi.cpp b/src/USER-MISC/fix_ipi.cpp
index 02cfcd9abb953c0e9c9c380e2d6af0318734e14a..58251a814e8fe26bfb5f5a8517d68d70ba8bf61f 100644
--- a/src/USER-MISC/fix_ipi.cpp
+++ b/src/USER-MISC/fix_ipi.cpp
@@ -319,12 +319,12 @@ void FixIPI::initial_integrate(int vflag)
   double *boxlo = domain->boxlo;
   double posconv;
   posconv=0.52917721*force->angstrom;
-  boxlo[0] = 0;
-  boxlo[1] = 0;
-  boxlo[2] = 0;
-  boxhi[0] = cellh[0]*posconv;
-  boxhi[1] = cellh[4]*posconv;
-  boxhi[2] = cellh[8]*posconv;
+  boxlo[0] = -0.5*cellh[0]*posconv;
+  boxlo[1] = -0.5*cellh[4]*posconv;
+  boxlo[2] = -0.5*cellh[8]*posconv;
+  boxhi[0] = -boxlo[0];
+  boxhi[1] = -boxlo[1];
+  boxhi[2] = -boxlo[2];
   domain->xy = cellh[1]*posconv;
   domain->xz = cellh[2]*posconv;
   domain->yz = cellh[5]*posconv;
@@ -421,7 +421,6 @@ void FixIPI::final_integrate()
       error->one(FLERR, "Got EXIT message from i-PI. Now leaving!");
 
     if (strcmp(header,"GETFORCE    ") == 0 )  {
-
       writebuffer(ipisock,"FORCEREADY  ",MSGLEN, error);
       writebuffer(ipisock,(char*) &pot,8, error);
       writebuffer(ipisock,(char*) &nat,4, error);
@@ -432,7 +431,6 @@ void FixIPI::final_integrate()
     }
     else
       error->one(FLERR, "Wrapper did not ask for forces, I will now die!");
-
   }
 
   hasdata=0;