yade-dev team mailing list archive

[noreply@xxxxxxxxxxxxx]

------------------------------------------------------------
revno: 3703
committer: Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>
timestamp: Thu 2013-08-29 12:30:31 +0200
message:
  - remove Dem3Dof from documentation
modified:
  doc/sphinx/formulation.rst
  doc/sphinx/introduction.rst
  doc/sphinx/prog.rst
  doc/sphinx/user.rst


--
lp:yade
https://code.launchpad.net/~yade-pkg/yade/git-trunk

Your team Yade developers is subscribed to branch lp:yade.
To unsubscribe from this branch go to https://code.launchpad.net/~yade-pkg/yade/git-trunk/+edit-subscription

=== modified file 'doc/sphinx/formulation.rst'
--- doc/sphinx/formulation.rst	2013-05-14 21:24:11 +0000
+++ doc/sphinx/formulation.rst	2013-08-29 10:30:31 +0000
@@ -314,8 +314,6 @@
 -------------
 In order to keep $\vec{u}_T$ consistent (e.g. that $\vec{u}_T$ must be constant if two spheres retain mutually constant configuration but move arbitrarily in space), then either $\vec{u}_T$ must track spheres' spatial motion or must (somehow) rely on sphere-local data exclusively.
 
-These two possibilities lead to two algorithms of computing shear strains. They should give the same results (disregarding numerical imprecision), but there is a trade-off between computational cost of the incremental method and robustness of the total one.
-
 Geometrical meaning of shear strain is shown in `fig-shear-2d`_.
 
 .. _fig-shear-2d:
@@ -323,9 +321,7 @@
 	
 	Evolution of shear displacement $\vec{u}_T$ due to mutual motion of spheres, both linear and rotational. Left configuration is the initial contact, right configuration is after displacement and rotation of one particle.
 
-Incremental algorithm
-^^^^^^^^^^^^^^^^^^^^^
-The incremental algorithm is widely used in DEM codes and is described frequently ([Luding2008]_, [Alonso2004]_). Yade implements this algorithm in the :yref:`ScGeom` class. At each step, shear displacement $\uT$ is updated; the update increment can be decomposed in 2 parts: motion of the interaction (i.e. $\vec{C}$ and $\vec{n}$) in global space and mutual motion of spheres.
+The classical incremental algorithm is widely used in DEM codes and is described frequently ([Luding2008]_, [Alonso2004]_). Yade implements this algorithm in the :yref:`ScGeom` class. At each step, shear displacement $\uT$ is updated; the update increment can be decomposed in 2 parts: motion of the interaction (i.e. $\vec{C}$ and $\vec{n}$) in global space and mutual motion of spheres.
 
 #. Contact moves dues to changes of the spheres' positions $\vec{C}_1$ and $\vec{C}_2$, which updates current $\currC$ and $\currn$ as per :eq:`eq-contact-point` and :eq:`eq-contact-normal`. $\prevuT$ is perpendicular to the contact plane at the previous step $\prevn$ and must be updated so that $\prevuT+(\Delta\uT)=\curruT\perp\currn$; this is done by perpendicular projection to the plane first (which might decrease $|\uT|$) and adding what corresponds to spatial rotation of the interaction instead:
   
@@ -353,74 +349,6 @@
 
 .. math:: \curruT=\prevuT+(\Delta\uT)_1 + (\Delta\uT)_2 + (\Delta\uT)_3.
 
-.. _sect-formulation-total-shear:
-
-Total algorithm
-^^^^^^^^^^^^^^^
-The following algorithm, aiming at stabilization of response even with large rotation speeds or $\Delta t$ approaching stability limit, was designed in [Smilauer2010b]_. (A similar algorithm based on total formulation, which covers additionally bending and torsion, was proposed in [Wang2009]_.) It is based on tracking original contact points (with zero shear) in the particle-local frame.
-
-In this section, variable symbols implicitly denote their current values unless explicitly stated otherwise.
-
-Shear strain may have two sources: mutual rotation of spheres or transversal displacement of one sphere with respect to the other. Shear strain does not change if both spheres move or rotate but are not in linear or angular motion mutually. To accurately and reliably model this situation, for every new contact the initial contact point $\bar{\vec{C}}$ is mapped into local sphere coordinates ($\vec{p}_{01}$, $\vec{p}_{02}$). As we want to determine the distance between both points (i.e. how long the trajectory in on both spheres' surfaces together), the shortest path from current $\vec{C}$ to the initial locally mapped point on the sphere's surface is „unrolled“ to the contact plane ($\vec{p}'_{01}$, $\vec{p}'_{02}$); then we can measure their linear distance $\uT$ and define shear strain $\vec{\eps}_T=\uT/d_0$ (fig. `fig-shear-displacement`_).
-
-More formally, taking $\bar{\vec{C}}_i$, $\bar{q}_i$ for the sphere initial positions and orientations (as quaterions) in global coordinates, the initial sphere-local contact point *orientation* (relative to sphere-local axis $\hat{x}$) is remembered:
-
-.. math::
-	:nowrap:
-	
-	\begin{align*}
-		\bar{\vec{n}}&=\normalized{{\vec{C}}_1-{\vec{C}}_2}, \\
-		\bar{q}_{01}&=\Align(\hat x,\bar{q}_1^*\bar{\vec{n}} \bar{q}_1^{**}), \\ 
-		\bar{q}_{02}&=\Align(\hat x,\bar{q}_2^* (-\bar{\vec{n}}) \bar{q}_2^{**}).
-	\end{align*}
-	
-.. (See \autoref{sect-quaternions} for definition of $\Align$.)
-
-				
-After some spheres motion, the original point can be "unrolled" to the current contact plane:
-
-.. math::
-	:nowrap:
-	
-	\begin{align*}
-		q&=\Align(\vec{n},q_1 \bar{q}_{01} \hat x (q_1 \bar{q}_{01})^*) \quad\hbox{(auxiliary)} \\
-		\vec{p}'_{01}&=q_{\theta}d_1(q_{\vec{u}} \times \vec{n})
-	\end{align*}
-
-where $q_{\vec{u}}$, $q_{\theta}$ are axis and angle components of $q$ and $p_{01}'$ is the unrolled point. Similarly,
-
-.. math::
-	:nowrap:
-
-	\begin{align*}
-		q&=\Align(\vec{n},q_2 \bar{q}_{02} \hat x (q_2 \bar{q}_{02})^*) \\
-		\vec{p}'_{02}&=q_{\theta}d_1(q_{\vec{u}} \times (-\vec{n})).
-	\end{align*}
-
-Shear displacement and strain are then computed easily:
-
-.. math::
-	:nowrap:
-
-	\begin{align*}
-		\uT&=\vec{p}'_{02}-\vec{p}'_{01} \\
-		\vec{\eps}_T&=\frac{\uT}{d_0}
-	\end{align*}
-
-When using material law with plasticity in shear, it may be necessary to limit maximum shear strain, in which case the mapped points are moved closer together to the requested distance (without changing $\hat{\vec{u}}_T$). This allows us to remember the previous strain direction and also avoids summation of increments of plastic strain at every step (`fig-shear-slip`_).
-
-.. _fig-shear-displacement:
-.. figure:: fig/shear-displacement.*
-
-	Shear displacement computation for two spheres in relative motion.
-
-
-.. _fig-shear-slip:
-.. figure:: fig/shear-slip.*
-
-	Shear plastic slip for two spheres.
-
-This algorithm is straightforwardly modified to facet-sphere interactions. In Yade, it is implemented by :yref:`Dem3DofGeom` and related classes.
 
 .. _sect-formulation-stress-cundall:
 

=== modified file 'doc/sphinx/introduction.rst'
--- doc/sphinx/introduction.rst	2013-08-14 08:01:55 +0000
+++ doc/sphinx/introduction.rst	2013-08-29 10:30:31 +0000
@@ -343,7 +343,7 @@
 :yref:`IGeom`
 	holding geometrical configuration of the two particles in collision; it is updated automatically as the particles in question move and can be queried for various geometrical characteristics, such as penetration distance or shear strain.
 	
-	Based on combination of types of :yref:`Shapes<Shape>` of the particles, there might be different storage requirements; for that reason, a number of derived classes exists, e.g. for representing geometry of contact between :yref:`Sphere+Sphere<Dem3DofGeom_SphereSphere>`, :yref:`Facet+Sphere<Dem3DofGeom_FacetSphere>` etc.
+	Based on combination of types of :yref:`Shapes<Shape>` of the particles, there might be different storage requirements; for that reason, a number of derived classes exists, e.g. for representing geometry of contact between :yref:`Sphere+Sphere<ScGeom>`, :yref:`Cylinder+Sphere<CylScGeom>` etc. Note, however, that it is possible to represent many type of contacts with the basic sphere-sphere geometry (for instance in :yref:`Ig2_Wall_Sphere_ScGeom`).
 :yref:`IPhys`
 	representing non-geometrical features of the interaction; some are computed from :yref:`Materials<Material>` of the particles in contact using some averaging algorithm (such as contact stiffness from Young's moduli of particles), others might be internal variables like damage.
 

=== modified file 'doc/sphinx/prog.rst'
--- doc/sphinx/prog.rst	2013-08-14 08:01:55 +0000
+++ doc/sphinx/prog.rst	2013-08-29 10:30:31 +0000
@@ -872,7 +872,7 @@
 
 .. code-block:: c++
 
-	class Ig2_Facet_Sphere_Dem3DofGeom: public IGeomFunctor{
+	class Ig2_Facet_Sphere_ScGeom: public IGeomFunctor{
 	   public:
 
 	   // override the IGeomFunctor::go
@@ -914,7 +914,7 @@
 
 If no functor is able to accept given types (first condition violated) or multiple functors have the same distance (in condition 2), an exception is thrown.
 
-This resolution mechanism makes it possible, for instance, to have a hierarchy of :yref:`Dem3DofGeom` classes (for different combination of shapes: :yref:`Dem3DofGeom_SphereSphere`, :yref:`Dem3DofGeom_FacetSphere`, :yref:`Dem3DofGeom_WallSphere`), but only provide a :yref:`LawFunctor` accepting ``Dem3DofGeom``, rather than having different laws for each shape combination.
+This resolution mechanism makes it possible, for instance, to have a hierarchy of :yref:`ScGeom` classes (for different combination of shapes), but only provide a :yref:`LawFunctor` accepting ``ScGeom``, rather than having different laws for each shape combination.
 
 .. note:: Performance implications of dispatch resolution are relatively low. The dispatcher lookup is only done once, and uses fast lookup matrix (1D or 2D); then, the functor found for this type(s) is cached within the ``Interaction`` (or ``Body``) instance. Thus, regular functor call costs the same as dereferencing pointer and calling virtual method. There is `blueprint <https://blueprints.launchpad.net/yade/+spec/devirtualize-functor-calls>`__ to avoid virtual function call as well.
 

=== modified file 'doc/sphinx/user.rst'
--- doc/sphinx/user.rst	2013-08-26 21:47:32 +0000
+++ doc/sphinx/user.rst	2013-08-29 10:30:31 +0000
@@ -418,7 +418,7 @@
 #. Approximate collision detection is adjusted so that approximate contacts are detected also between particles within the interaction radius. This consists in setting value of :yref:`Bo1_Sphere_Aabb.aabbEnlargeFactor` to the interaction radius value.
 
 #. The geometry functor (``Ig2``)
-   would normally say that "there is no contact" if given 2 spheres that are not in contact. Therefore, the same value as for :yref:`Bo1_Sphere_Aabb.aabbEnlargeFactor` must be given to it. (Either :yref:`Ig2_Sphere_Sphere_Dem3DofGeom.distFactor` or :yref:`Ig2_Sphere_Sphere_ScGeom.interactionDetectionFactor`, depending on the functor that is in use.
+   would normally say that "there is no contact" if given 2 spheres that are not in contact. Therefore, the same value as for :yref:`Bo1_Sphere_Aabb.aabbEnlargeFactor` must be given to it (:yref:`Ig2_Sphere_Sphere_ScGeom.interactionDetectionFactor` ).
 
    Note that only :yref:`Sphere` + :yref:`Sphere` interactions are supported; there is no parameter analogous to :yref:`distFactor<Ig2_Sphere_Sphere_ScGeom.interactionDetectionFactor>` in :yref:`Ig2_Facet_Sphere_ScGeom`. This is on purpose, since the interaction radius is meaningful in bulk material represented by sphere packing, whereas facets usually represent boundary conditions which should be exempt from this dense interaction network.
 
@@ -576,12 +576,7 @@
    
    Again, missing combination will cause given shape combinations to freely interpenetrate one another.
 
-#. :yref:`IGeom` type accepted by the ``Law2`` functor (below); it is the first part of functor's name after ``Law2`` (for instance, :yref:`Law2_ScGeom_CpmPhys_Cpm` accepts :yref:`ScGeom`). This is (for most cases) either :yref:`Dem3DofGeom` (total shear formulation) or :yref:`ScGeom` (incremental shear formulation). For :yref:`Dem3DofGeom`, the above example would simply change to::
-
-      InteractionLoop([
-         Ig2_Sphere_Sphere_Dem3DofGeom(),
-         Ig2_Facet_Sphere_Dem3DofGeom()
-      ],[],[])
+#. :yref:`IGeom` type accepted by the ``Law2`` functor (below); it is the first part of functor's name after ``Law2`` (for instance, :yref:`Law2_ScGeom_CpmPhys_Cpm` accepts :yref:`ScGeom`).
 
 Ip2 functors
 ^^^^^^^^^^^^