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! ------------------------------------------------------------------------------
!
! Gmsh Fortran tutorial 17
!
! Anisotropic background mesh
!
! ------------------------------------------------------------------------------
! As seen in `t7.f90', mesh sizes can be specified very accurately by providing a
! background mesh, i.e., a post-processing view that contains the target mesh
! sizes.
! Here, the background mesh is represented as a metric tensor field defined on a
! square. One should use bamg as 2d mesh generator to enable anisotropic meshes
! in 2D.
program t17
use, intrinsic :: iso_c_binding
use gmsh
implicit none
type(gmsh_t) :: gmsh
integer(c_int) :: bg_field, ret
character(len=GMSH_API_MAX_STR_LEN) :: cmd
call gmsh%initialize()
call gmsh%model%add("t17")
! Create a square
ret = gmsh%model%occ%addRectangle(-2d0, -2d0, 0d0, 4d0, 4d0)
call gmsh%model%occ%synchronize()
! Merge a post-processing view containing the target anisotropic mesh sizes
call gmsh%merge('../t17_bgmesh.pos')
! Apply the view as the current background mesh
bg_field = gmsh%model%mesh%field%add("PostView")
call gmsh%model%mesh%field%setNumber(bg_field, "ViewIndex", 0d0)
call gmsh%model%mesh%field%setAsBackgroundMesh(bg_field)
! Use bamg
call gmsh%option%setNumber("Mesh.SmoothRatio", 3d0)
call gmsh%option%setNumber("Mesh.AnisoMax", 1000d0)
call gmsh%option%setNumber("Mesh.Algorithm", 7d0)
call gmsh%model%mesh%generate(2)
call gmsh%write("t17.msh")
! Launch the GUI to see the results:
call get_command(cmd)
if (index(cmd, "-nopopup") == 0) call gmsh%fltk%run()
call gmsh%finalize()
end program t17
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