diff --git a/Plugin/Particles.cpp b/Plugin/Particles.cpp
index 35d280ca0276d0b5f091d199c55e0dbb33c79b55..963056e14ed1b495486ab4b7773246db0ca8aa71 100644
--- a/Plugin/Particles.cpp
+++ b/Plugin/Particles.cpp
@@ -229,7 +229,7 @@ PView *GMSH_ParticlesPlugin::execute(PView *v)
   PView *v2 = new PView();
   PViewDataList *data2 = getDataList(v2);
 
-  // Solve 'A2 d^2x/dt^2 + A1 dx/dt + A0 x = F' using a Newmark scheme:
+  // solve 'A2 d^2x/dt^2 + A1 dx/dt + A0 x = F' using a Newmark scheme:
   //
   // (A2 + gamma DT A1 + beta DT^2 A0) x^{n+1} =
   //   (2 A2 - (1 - 2 gamma) DT A1 - (0.5 + gamma - 2 beta) DT^2 A0) x^n +
@@ -257,7 +257,7 @@ PView *GMSH_ParticlesPlugin::execute(PView *v)
         double F[3], X[3];
         o1.searchVector(X1[0], X1[1], X1[2], F, timeStep);
         for(int k = 0; k < 3; k++)
-          X[k] = 1 / c1 * (c2 * X1[k] + c3 * X0[k] + c4 * F[k]);
+          X[k] = (c2 * X1[k] + c3 * X0[k] + c4 * F[k]) / c1;
         data2->VP.push_back(X[0] - XINIT[0]);
         data2->VP.push_back(X[1] - XINIT[1]);
         data2->VP.push_back(X[2] - XINIT[2]);
diff --git a/doc/texinfo/gmsh.texi b/doc/texinfo/gmsh.texi
index 75f0a075ce81d83c221ecb38103f7d4e35239533..8fec6b72ea5d30ea0de9236177ae1d0c9e9fb415 100644
--- a/doc/texinfo/gmsh.texi
+++ b/doc/texinfo/gmsh.texi
@@ -2224,7 +2224,7 @@ elementary surfaces should be oriented consistently (using negative
 identification numbers to specify reverse orientation). (Surface loops are
 used to create volumes: see @ref{Volumes}.)
 
-@item Compound Surface ( @var{expression} ) = @{ @var{expression-list} @} < Boundary @{ @{ @var{expression-list} @}, @{ @var{expression-list} @}, @{ @var{expression-list} @}, @{ @var{expression-list} @} @} >;
+@item Compound Surface ( @var{expression} ) = @{ @var{expression-list} @} < Boundary @{ @{ @var{expression-list} @}, @{ @var{expression-list} @}, @{ @var{expression-list} @}, @{ @var{expression-list} @} @} > < Harmonic | Conformal | Harmonic_NoSplit | Conformal_NoSplit >;
 Creates a compound surface from several elementary surfaces.  When
 meshed, a compound surface will be reparametrized as a single surface,
 whose mesh can thus cross internal boundaries. Compound surfaces are
@@ -2237,7 +2237,7 @@ mandatory @var{expression-list} on the right hand side contains the
 identification number of the elementary surfaces that should be
 reparametrized as a single surface.
 
-@c TODO document the optional @code{Boundary} arguments.
+@c TODO document the optional arguments.
 
 @item Physical Surface ( @var{expression} | @var{char-expression} ) = @{ @var{expression-list} @};
 Creates a physical surface. The @var{expression} inside the parentheses