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{ MESH_DENSITY.PDE  

 

  This example demonstrates the use of the MESH_DENSITY parameter to

  control mesh density.

 

  A global density function is defined as a Gaussian distribution returning

  1 cell-per-unit density at the center, rising to 54.6 cell-per-unit density

  at the corners.

 

  This global distribution is overridden by a regional definition of 50 cell-per-unit

  density in a central region.

 

}

title 'Cell Size Control'

variables

   u

definitions

   k = 1

   u0 = 1-x^2-y^2

   s = 2*3/4+5*2/4

  mesh_density = exp(2*(x^2+y^2))

   box = 0.1

equations

   u : div(K*grad(u)) +s = 0

boundaries

  Region 1

      start(-1,-1)

          value(u)=u0

      line to (1,-1) to (1,1) to (-1,1) to close

  Region 2

      mesh_density = 50

      start(-box,-box)

      line to (box,-box) to (box,box) to (-box,box) to close

plots

  grid(x,y)

  contour(u)

end