OPTIM_TWIND_nl.sif

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!! Test for Weertman friction law            !!
!!  optimise the Weertman friction coefficient!
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! OPTIMISATION PARAMETERS
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!! Name of the RUN 
$name="TWIND_nl"
!! Regularisation parameter
$Lambda=0.0
!! max. number of iterations
$niter=50
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!! TEST PARAMETERS
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$L = 20.0e3
$Slope = 0.1 * pi / 180.0
!### physical constants
$yearinsec = 365.25*24*60*60
$rhoi = 900.0/(1.0e6*yearinsec^2)
$gravity = -9.81*yearinsec^2
$n = 3.0
$eta = (2.0*100.0)^(-1.0/n)
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Header
  Mesh DB "." "rectangle"
End
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Simulation
  Coordinate System  = Cartesian 3D
  Simulation Type = Steady State

  ! Internal extrusion
  Extruded Mesh Levels = Integer 5

  Steady State Min Iterations = 1
  Steady State Max Iterations = $niter

  Post File = "OPTIM_$name$_.vtu"
  OutPut Intervals = 1

  !! restart True solution
  Restart File = "Direct_nl.result"
  Restart Before Initial Conditions = logical True

  max output level = 3
End

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!! Bodies
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Body 1
  Equation = 1
  Body Force = 1
  Material = 1
  Initial Condition = 1
End
! Top surface
Body 2
  Equation = 2
  Initial Condition = 2
  Body Force = 2
End
! Bottom Surface
Body 3
  Equation = 3
  Initial Condition = 3
End

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!! Initial Conditions
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Initial Condition 1
  Uobs  1 = Equals Velocity 1
  Uobs  2 = Equals Velocity 2
  Uobs  3 = Equals Velocity 3
End

! Top surface
Initial Condition 2
End

! Bottom Surface
Initial Condition 3
!! Slip Coefficient

 ! Initial guess
 alpha = Real -2.5

End

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!!  Body Forces
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Body Force 1
  Flow BodyForce 1 = Real 0.0
  Flow BodyForce 2 = Real 0.0
  Flow BodyForce 3 = Real $gravity
End

Body Force 2
 Adjoint Cost = Variable Velocity 1, Uobs 1, Velocity 2, Uobs 2
   Real MATC "0.5*(tx[0]-tx[1])*(tx[0]-tx[1])+0.5*(tx[2]-tx[3])*(tx[2]-tx[3])"

 Adjoint Cost der 1 = Variable Velocity 1, Uobs 1
   Real MATC "(tx[0]-tx[1])"
 Adjoint Cost der 2 = Variable Velocity 2, Uobs 2
   Real MATC "(tx[0]-tx[1])"
End

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!! Materials
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Material 1
  Density = Real $rhoi
  Viscosity Model = String "power law"
  Viscosity = Real $eta
  Viscosity Exponent = Real $1.0/n
  Critical Shear Rate = Real 1.0e-10
End

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!! Solvers
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!! Before simulation
Solver 1
  Exec Solver = before simulation
  Equation = "MapCoordinate"
  Procedure = "StructuredMeshMapper" "StructuredMeshMapper"

  Active Coordinate = Integer 3
End

!! Always

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!! Velocity solution
!!  body 1 (bulk)
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Solver 2
  Equation = "Stokes-Vec"
  Procedure = "IncompressibleNSVec" "IncompressibleNSSolver"

  Stokes Flow = logical true
  
  Div-Curl Discretization = Logical False
  Element = "p:1 b:10"
  !Relative Integration Order = -1

  !linear settings:
  !------------------------------
  Linear System Solver = Iterative
  Linear System Iterative Method = GCR
  Linear System Preconditioning= ILU0
  Linear System Convergence Tolerance= 1.0e-10
  Linear System Max Iterations = 500

  Linear System Residual Output = 100

  Linear System Abort Not Converged = False


  !Non-linear iteration settings:
  !------------------------------ 
  Nonlinear System Max Iterations = 50
  Nonlinear System Convergence Tolerance  = 1.0e-8
  Nonlinear System Newton After Iterations = 5
  Nonlinear System Newton After Tolerance = 1.0e-4
  Nonlinear System Reset Newton = Logical True


  Steady State Convergence Tolerance = Real 1.0e-12

! Create variables required for the optimisation
  Exported Variable 1 = -global CostValue 
  Exported Variable 2 = -nooutput "Velocityb"
  Exported Variable 2 DOFs = 4
  Exported Variable 3 = "Uobs"
  Exported Variable 3 DOFs = 3
End

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!! Cost Function
!!  body 2 (top)
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Solver 3
 Equation = "Cost"
    procedure = "ElmerIceSolvers" "Adjoint_CostContSolver"

   Cost Variable Name = String "CostValue"  ! Name of Cost Variable
 ! save the cost as a function of iterations (iterations,Cost,rms=sqrt(2*Cost/Area)
   Cost Filename = File "Cost_$name$.dat"

  Sensitivity Variable Name = String "velocityb"

end

!!!!!!!!!!!!!!!!!!!!!!!!
!!  Adjoint 
!!  body 1 (bulk)
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Solver 4
  Equation = "Adjoint"
  Variable = -nooutput Adjoint
  Variable Dofs = 4

  procedure = "ElmerIceSolvers" "Adjoint_LinearSolver"

!## When using Stokes_vec
  Bubbles in Global System = FALSE
  Element = string "p:1 -tri b:1 -tetra b:1 -quad b:3 -brick b:4 -prism b:4 -pyramid b:4"


!Name of the flow solution solver
  Direct Solver Equation Name = string "Stokes-Vec"

! linear system
  Linear System Solver = Iterative
  Linear System Iterative Method = GCR
  Linear System Preconditioning= ILU0
  Linear System Convergence Tolerance= 1.0e-10
  Linear System Max Iterations = 1000

End

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!!  Derivative / beta
!!  body 3 (bottom)
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Solver 5
 Equation = "DJDBeta"
    procedure = "ElmerIceSolvers" "AdjointStokes_GradientBetaSolver"

    Flow Solution Name = String "Flow Solution"
    Adjoint Solution Name = String "Adjoint"
    Gradient Variable Name = String "DJDalpha"

!## When using Stokes_vec
  Bubbles in Global System = FALSE
  Element = string "p:1 -tri b:1 -tetra b:1 -quad b:3 -brick b:4 -prism b:4 -pyramid b:4"

  !! Exported Variables
    Exported Variable 1 = alpha
    Exported Variable 2 = DJDalpha
End

!!!!!!!!!!!!!!!!!!!!!!!!
!!  Regularisation
!!  body 3 (bottom)
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Solver 6
  Equation = "DJDBeta_Reg"
    procedure = "ElmerIceSolvers" "Adjoint_CostRegSolver"

    Cost Filename=File "CostReg_$name$.dat"
    Optimized Variable Name= String "alpha"
    Gradient Variable Name= String "DJDalpha"
    Cost Variable Name= String "CostValue"
    Lambda= Real $Lambda
    Reset Cost Value= Logical False  !=> DJDapha already initialized in solver DJDBeta; switch off initialisation to 0 at the beginning of this solver
    A priori Regularisation= Logical False
end

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!!  Optimisation
!!  body 3 (bottom)
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Solver 7
  Equation = "Optimize_m1qn3"
  procedure = "ElmerIceSolvers" "Optimize_m1qn3Parallel"

!## When using Stokes_vec
  Bubbles in Global System = FALSE

  Cost Variable Name = String "CostValue"
  Optimized Variable Name = String "alpha"
  Gradient Variable Name = String "DJDalpha"
  gradient Norm File = File "GradientNormAdjoint_$name$.dat"

  !!
  Mesh Independent = Logical FALSE

 ! M1QN3 Parameters
  M1QN3 dxmin = Real 1.0e-10
  M1QN3 epsg = Real  1.e-6
  M1QN3 niter = Integer $niter
  M1QN3 nsim = Integer $niter
  M1QN3 impres = Integer 5
  M1QN3 DIS Mode = Logical True
  M1QN3 df1 = Real 0.5
  M1QN3 normtype = String "dfn"
  M1QN3 OutputFile = File  "M1QN3_$name$.out"
  M1QN3 ndz = Integer 20

end

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!! Equations
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! bulk
Equation 1
  Active Solvers(3) = 1 2 4
End
! Top
Equation 2
  Active Solvers(1) = 3
End
! bottom
Equation 3
  Active Solvers(3) = 5 6 7
End

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!! Boundary Conditions
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!!! BC (y=y0)    
Boundary Condition 1
  Target Boundaries = 1
  Velocity 1  = Equals Uobs 1
  Velocity 2  = Equals Uobs 2
  Velocity 3  = Equals Uobs 3
End

!!! BC (x=xmax) 
Boundary Condition 2
  Target Boundaries = 2
  Velocity 1  = Equals Uobs 1
  Velocity 2  = Equals Uobs 2
  Velocity 3  = Equals Uobs 3
End

!!! BC (y=ymax)   
Boundary Condition 3
  Target Boundaries = 3
  Velocity 1  = Equals Uobs 1
  Velocity 2  = Equals Uobs 2
  Velocity 3  = Equals Uobs 3
End

!!! BC  (x=x0) 
Boundary Condition 4
  Target Boundaries = 4
  Velocity 1  = Equals Uobs 1
  Velocity 2  = Equals Uobs 2
  Velocity 3  = Equals Uobs 3
End

Boundary Condition 5
  Name = "bottom"
  Body Id = 3

 !! Normal-Tangential coordinate system
    Normal-Tangential Velocity = Logical True
    Velocity 1 = Real 0.0

  Weertman Friction Coefficient = Variable alpha
    REAL procedure "ElmerIceUSF" "TenPowerA"
  Weertman Exponent = Real 0.3333333333333333333
! Cut-off such that argument is not smaller than this
  Friction Linear Velocity = Real 1.0e-4

  Slip Coefficient derivative = Variable alpha
    REAL procedure "ElmerIceUSF" "TenPowerA_d"

 Bottom Surface = Variable Coordinate 1
     Real MATC "-tx*tan(Slope)-1000.0"
End

!!! free surface
Boundary Condition 6
  Body Id = 2

  Top Surface = Variable Coordinate 1
     Real MATC "-tx*tan(Slope)"
End


!### REFERENCE SOLUTION
Solver 3 :: Reference Norm = 2.49042560E+04
Solver 3 :: Reference Norm Tolerance = Real 1.0e-5