Small doc page clarifications

doc/src/fix_deform.rst

@@ -64,6 +64,8 @@ Syntax
                  effectively an engineering shear strain rate
            *erate* value = R
              R = engineering shear strain rate (1/time units)
+           *erate/rescale* value = R (ONLY available in :doc:`fix deform/pressure <fix_deform_pressure>` command)
+             R = engineering shear strain rate (1/time units)
            *trate* value = R
              R = true shear strain rate (1/time units)
            *wiggle* values = A Tp

doc/src/fix_wall_gran.rst

@@ -115,6 +115,17 @@ friction and twisting friction supported by the :doc:`pair_style granular <pair_
 supported for walls. These are discussed in greater detail on the doc
 page for :doc:`pair_style granular <pair_granular>`.
 
+.. note::
+   When *fstyle* *granular* is specified, the associated *fstyle_params* are taken as
+   those for a wall–particle interaction. For example, for the hertz/material normal
+   contact model with :math:`E = 960` and :math:`\nu= 0.2`, the effective Young’s
+   modulus for a wall–particle interaction is computed as :math:`E_{eff} = \frac{960}
+   {2(1-0.2^2)} = 500`. Any pair coefficients defined by :doc:`pair_style granular
+   <pair_granular>` are not taken into consideration. To model different
+   wall–particle interactions for particles of different material types, the user may
+   define multiple fix wall/gran commands operating on separate groups (e.g. based
+   on particle type) each with a different wall–particle effective Young's modulus.
+
 Note that you can choose a different force styles and/or different
 values for the wall/particle coefficients than for particle/particle
 interactions.  E.g. if you wish to model the wall as a different

doc/src/pair_granular.rst

@@ -111,7 +111,7 @@ For the *hertz* model, the normal component of force is given by:
 
    \mathbf{F}_{ne, Hertz} = k_n R_{eff}^{1/2}\delta_{ij}^{3/2} \mathbf{n}
 
-Here, :math:`R_{eff} = \frac{R_i R_j}{R_i + R_j}` is the effective
+Here, :math:`R_{eff} = R = \frac{R_i R_j}{R_i + R_j}` is the effective
 radius, denoted for simplicity as *R* from here on.  For *hertz*, the
 units of the spring constant :math:`k_n` are *force*\ /\ *length*\ \^2, or
 equivalently *pressure*\ .
@@ -120,13 +120,14 @@ For the *hertz/material* model, the force is given by:
 
 .. math::
 
-   \mathbf{F}_{ne, Hertz/material} = \frac{4}{3} E_{eff} R_{eff}^{1/2}\delta_{ij}^{3/2} \mathbf{n}
+   \mathbf{F}_{ne, Hertz/material} = \frac{4}{3} E_{eff} R^{1/2}\delta_{ij}^{3/2} \mathbf{n}
 
-Here, :math:`E_{eff} = E = \left(\frac{1-\nu_i^2}{E_i} + \frac{1-\nu_j^2}{E_j}\right)^{-1}` is the effective Young's
-modulus, with :math:`\nu_i, \nu_j` the Poisson ratios of the particles of
-types *i* and *j*\ . Note that if the elastic modulus and the shear
-modulus of the two particles are the same, the *hertz/material* model
-is equivalent to the *hertz* model with :math:`k_n = 4/3 E_{eff}`
+Here, :math:`E_{eff} = E = \left(\frac{1-\nu_i^2}{E_i} + \frac{1-\nu_j^2}{E_j}\right)^{-1}`
+is the effective Young's modulus, with :math:`\nu_i, \nu_j` the Poisson ratios
+of the particles of types *i* and *j*. :math:`E_{eff}` is denoted as *E* from here on.
+Note that if the elastic modulus and the shear modulus of the two particles are the
+same, the *hertz/material* model is equivalent to the *hertz* model with
+:math:`k_n = 4/3 E`
 
 The *dmt* model corresponds to the
 :ref:`(Derjaguin-Muller-Toporov) <DMT1975>` cohesive model, where the force
@@ -417,11 +418,11 @@ discussion above. To match the Mindlin solution, one should set
 
    G_{eff} = \left(\frac{2-\nu_i}{G_i} + \frac{2-\nu_j}{G_j}\right)^{-1}
 
-where :math:`G` is the shear modulus, related to Young's modulus :math:`E`
-and Poisson's ratio :math:`\nu` by :math:`G = E/(2(1+\nu))`. This can also be
-achieved by specifying *NULL* for :math:`k_t`, in which case a
-normal contact model that specifies material parameters :math:`E` and
-:math:`\nu` is required (e.g. *hertz/material*, *dmt* or *jkr*\ ). In this
+where :math:`G_i` is the shear modulus of a particle of type :math:`i`, related to Young's
+modulus :math:`E_i` and Poisson's ratio :math:`\nu_i` by :math:`G_i = E_i/(2(1+\nu_i))`.
+This can also be achieved by specifying *NULL* for :math:`k_t`, in which case a
+normal contact model that specifies material parameters :math:`E_i` and
+:math:`\nu_i` is required (e.g. *hertz/material*, *dmt* or *jkr*\ ). In this
 case, mixing of the shear modulus for different particle types *i* and
 *j* is done according to the formula above.
 
@@ -551,7 +552,7 @@ opposite torque on each particle, according to:
 
 .. math::
 
-   \tau_{roll,i} =  R_{eff} \mathbf{n} \times \mathbf{F}_{roll}
+   \tau_{roll,i} =  R \mathbf{n} \times \mathbf{F}_{roll}
 
 .. math::