=====  =====
==== General Information ====

  * **Solver Fortran File:** ''MMG2DSolver.F90''
  * **Solver Name:** ''ElmerIce_MeshAdapt2D(MMG2DSolver)''
  * **Required Output Variable(s):** 
    * (1) ''dumy'' 
  * **Required Input Variable(s):** 
    * (1) ''Metric''
  * **Optional Output Variable(s):** None  
  * **Optional Input Variable(s):** None

==== General Description ====
This is a pseudo solver (i.e. it is not solving an equation). This solver is used for the mesh adaptation ([[mesh:meshadaptation|Mesh Adaptation]]). 

This solver call the Mmg library (http://www.mmgtools.org/) to perform the mesh adaptation. This require to separately install the Mmg code (https://github.com/MmgTools/mmg). 
This solver is included only if the //cmake// arguments  “MMG_INCLUDE_DIR” and “MMG_LIBRARY” are provided when compiling //elmerice//.

It will performed isotropic or anisotropic 2D mesh adaptation depending on the //dofs// of the //Input Variable//:
  * If //dofs//=1, it must contain the required element size at the current node location
  * If //dofs//=3, it must contain the components (M11,M22,M12) of the anisotropic metric (see [[mesh:meshadaptation|Mesh Adaptation]])

Our implementation is actually restricted to the adaptation of plane-view 2D meshes comprised of linear 3-nodes triangular elements. 

Tested with Mmg master branch commit (6acfa9e7b20e41134d56af10eba1bb8fd1283f8f).
==== SIF contents ====
<code>

Solver 1
  Exec Solver = after timestep

  Equation = "MMG"
  Variable = -nooutput dumy
    Procedure = "ElmerIce_MeshAdapt2D" "MMG2DSolver"

!! Name of the adapted mesh (will be used to save the mesh on disk)
  Output file name = "square_aniso"

!! Name of the variable that contain the metric; 
  !! Anisotropic 2D mesh adaptation if M is of size 3 (M11,M22,M12)
  !! Isotropic 2D mesh adaptation if M is of size 1 
  Metric Variable Name = String "M" 
  

!! Mmg parameters (see Mmg documentation for more information)
  hausd = Real 1000.0 !Hausdorff parameter (controls the refinement near boundaries)
  hgrad = Real 1.3  !gradation value (controls the ratio between two adjacent edges)

  verbosity = Integer 10 !Mmg verbosity

End

</code>


Boundary condition sections must be present to affect a boundary condition //Id// to the new boundary elements.
<code>
Boundary Condition X
!! The adapted mesh boundary elements will receive the //Id//: **X**
  Target Boundaries = Y
End

</code>


==== Example ====
An example for isotropic mesh adaptation can be found under ''[ELMER_TRUNK]/elmerice/Tests/MMG2D_Iso''. \\
Examples for anisotropic mesh adaptation can be found under ''[ELMER_TRUNK]/elmerice/Tests/MMG2D_Aniso1'' and ''[ELMER_TRUNK]/elmerice/Tests/MMG2D_Aniso2'', where the mesh size is adapted using 1 or 2 variables (i.e. combining metric informations), respectively.