Creating custom syntax for LPBF process

[KamalnathOSU]

Hi @GiudGiud ,

I have an moose input file to simulate LPBF (Laser Power-Bed-Fusion) process : #31878
Now, I want to simplify my input file using custom syntax by creating an action. I am following the guidelines on Action system. I have a few questions regarding the action.

1. It looks like my custom action should inherit from MooseObjectAction as I am simply trying to recreate the input blocks from my input file. In which cases, the user would have to inherit from Action ?

2. Instead of creating new tasks, I am thinking to associate my custom actions to pre-existing tasks in MOOSE such as add_aux_variable and add_variable. Is there any page in MOOSE that shows the list of available tasks ? to which I can associate my action.

3. In my act(), can I directly access the name of the syntax blocks in the input file ?

[MyCustomAction]
[./test1]
type=AddVariable
[../]
[]

For example, in the above input file block, can I get the string test1 which is the name of the input block while writing my action ?

FYI: My full input file is given below.

alloy='Ti64'

min_lo=25e-6
L_zmax=${fparse 2000e-6}
powder_layer_thickness = ${fparse 50e-6}

dt=${fparse 20.0e-7}
dtmin=${fparse dt/1000.0}
end_time=${fparse 10e-3} #  sec
output_dt=${fparse end_time/100}

# Model parameters
power=171.6 # in W
heat_scale=1
beam_velocity=0.2 # m/s
beam_radius=25e-6 # in m
OPD=600e-6 # in m 
## Radiation and Convective losses
TK_amb=298.15 # in K , Ambient temperature
emissivity = 0.3 # Surface emissivity
h_amb=20 # W/m^2/K , heat convective coefficient

[Variables]
  [TK]
  []
[]

[AuxVariables]
        [./SDV_bulk]
                order = CONSTANT
                family = MONOMIAL
        [../]
        [./TK_elem]
                order = CONSTANT 
                family = MONOMIAL
        [../]
[]

[AuxKernels]
        [./update_TK_elem]
                type = ProjectionAux
                variable = 'TK_elem'
                 v = 'TK'
                execute_on='INITIAL TIMESTEP_BEGIN TIMESTEP_END'
        [../]
      [./update_SDV]
          type = AuxBulkSDV
          variable = SDV_bulk
          temperature = TK_elem
          Tcritical = Tliq
          execute_on='INITIAL TIMESTEP_BEGIN TIMESTEP_END'
      [../]
[]

[ICs]
  [TK_substrate]
    type = ConstantIC
    variable = TK
    value = ${TK_amb}
  []

  [./SDV_ic]
    type = FunctionIC
    variable = 'SDV_bulk'
    function = 'SDV_initial_func'
  [../]
[]

[Kernels]
  [time]
    type = ADHeatConductionTimeDerivative
    variable = TK
  []
  [heat_conduct]
    type = ADHeatConduction
    variable = TK
    thermal_conductivity = thermal_conductivity
  []
  [heatsource]
    type = ADMatHeatSource
    material_property = volumetric_heat
    variable = TK
    scalar = 1
  []
[]

[BCs]
 #inactive='TK_back_fix'
  [TK_back_fix]
    type = ADDirichletBC
    variable = TK
    boundary = back
    value = ${TK_amb}
  []
  [TK_bottom_fix]
    type = ADNeumannBC
    variable = TK
    boundary = bottom
    value = 0
  []
  [TK_front_radiation]
    type = ADFunctionRadiativeBC
    variable = TK
    boundary = front
    emissivity_function = '${emissivity}'
    Tinfinity = ${TK_amb}
  []
  [TK_front_convection]
    type = ADConvectiveHeatFluxBC
    variable = TK
    boundary = front
    T_infinity = ${TK_amb}
    heat_transfer_coefficient = ${h_amb}
  []
[]

[Postprocessors]
  [avg_TK]
    type = ElementAverageValue
    variable = TK
  []
  [max_TK]
    type = ElementExtremeValue
    variable = TK
    value_type = max
  []
  [min_TK]
    type = ElementExtremeValue
    variable = TK
    value_type = min
  []
[]

[Executioner]
  type = Transient

  automatic_scaling = true

  solve_type = 'NEWTON'
  scheme = 'bdf2'

# petsc_options_iname = '-pc_type -sub_pc_type '
# petsc_options_value = 'asm      lu'
# line_search = 'none'

  l_max_its = 20
  nl_max_its = 20
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-10

  start_time = 0.0
  end_time = ${end_time}
  dtmin = ${dtmin}
  
  [TimeStepper]
    type = IterationAdaptiveDT
    dt = ${dt}
    optimal_iterations = 5
    iteration_window = 2
    #linear_iteration_ratio = 2
    cutback_factor_at_failure = 0.1
  []

[]

[Mesh]
        [fmg]
                type = FileMeshGenerator
                file = 'refined_mesh.e'
                use_for_exodus_restart = False
                skip_partitioning=False
        []
[]


[Functions]
  [heat_source_x]
    type = ParsedFunction
    expression = '400e-6+${beam_velocity}*t'
  []
  [heat_source_y]
    type = ParsedFunction
    expression = '0.0'
  []
  [heat_source_z]
    type = ParsedFunction
    expression = '${L_zmax}'
  []
          [./SDV_initial_func]
                type=ParsedFunction
                expression = ' if(z<zcri,1,0)'
                symbol_names =  'zcri'
                symbol_values = '${fparse L_zmax-powder_layer_thickness}'
        [../]
[]

[Preconditioning]
  [./smp]
    type = SMP
    full = true
  [../]
[]

[Materials]
  [volumetric_heat]
    type = ADFunctionPathVaniniHeatSource
    r = ${beam_radius} # in m
    OPD = ${OPD}
    power = ${power}
    efficiency = 0.7
    factor = ${heat_scale}
    function_x = heat_source_x
    function_y = heat_source_y
    function_z = heat_source_z
    heat_source_type = 'mixed'
    threshold_length = '${min_lo}'
    outputs='out'
  []
          [./powderbed]
                type = PowderBedProp
                temperature = TK
                AlloyParamName=${alloy} # Ti64, 316L, SDSS
                SDV_bulk = SDV_bulk
                outputs='out'
        [../]
[]

[Outputs]
  csv = true
  [./out]
      type = Exodus
      min_simulation_time_interval=${output_dt}
  [../]
  [./cp]
       type = Checkpoint
       time_step_interval = 10
       num_files = 2
  [../]
[]

[KamalnathOSU]

Actually, I am still not clear whether my action should inherit from Action or MooseObjectAction. You guidance on this matter would be very helpful.

[GiudGiud]

Hello

Actually, I am still not clear whether my action should inherit from Action or MooseObjectAction

MooseObjectAction ONLY if the action creates objects one by one.
I m thinking you actually want to be creating a class deriving from PhysicsBase actually. It depends on the syntax you want.

It looks like my custom action should inherit from MooseObjectAction as I am simply trying to recreate the input blocks from my input file. In which cases, the user would have to inherit from Action ?

Action as the base class (or PhysicsBase) is when the action creates more than one object of different types.
PhysicsBase is intended to create a whole equation in a single action.
See some examples in the framework using the Diffusion Physics and in the Navier Stokes module using the flow/energy/scalar/turbulence physics to see if that is the syntax you want

Instead of creating new tasks, I am thinking to associate my custom actions to pre-existing tasks in MOOSE such as add_aux_variable and add_variable. Is there any page in MOOSE that shows the list of available tasks ? to which I can associate my action.

Yes see Moose.C for all the tasks and the syntax they are associated with.
HeatTransferApp.C will show you how to register new actions/tasks

In my act(), can I directly access the name of the syntax blocks in the input file ?

Yes, the name of the syntax block here is accessed using name().

[KamalnathOSU]

Hi @GiudGiud ,
I have a syntax error on Action which I can use your help.
I am writing an action called "SetupBaseLPBF" inheriting from "Action" class. I want to move the following input block into the act() method.

[Mesh]
        [fmg]
                type = FileMeshGenerator
                file = 'refined_mesh.e'
                use_for_exodus_restart = False
                skip_partitioning=False
        []
[]

I register the action with the task in my SetupBaseLPBF.C

registerMooseAction("MalamuteApp", SetupBaseLPBF, "add_mesh_generator");

I have the following block in my act() method:

if(_current_task == "add_mesh_generator" && !_input_mesh.empty() ){
  const std::string type = "FileMeshGenerator";
  InputParameters params = _factory.getValidParams(type);
  
  //Setup parameters
  params.set<MeshFileName>("file") = _input_mesh;
  params.set<bool>("use_for_exodus_restart") =false;
  params.set<bool>("skip_partitioning") = false;

  _problem.addMeshGenerator(type, "fmg", params); // I get syntax error in this method. Please, suggest me how to fix it.  
} 

But it looks like, we don't have addMeshGenerator() method. Which method should I use to accomplish mesh creation ?

[KamalnathOSU]

Thank you for catching that. After adding "MoosePreconditioner.h", it is able to recognize MoosePreconditioner class. But now, I am getting a different error as shown below.

Checking if header needs updating: /home/kamalnath/projects/malamute/moose/framework/include/base/MooseRevision.h...
Checking if header needs updating: /home/kamalnath/projects/malamute/include/base/MalamuteRevision.h...
Creating Unity /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.C
Compiling C++ (in opt mode) /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.C...
In file included from /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.C:2:
/home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C: In member function 'virtual void SetupBaseLPBF::act()':
/home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:356:13: error: 'NonlinearSystemBase& MoosePreconditioner::_nl' is protected within this context
  356 |         pc->_nl.setPreconditioner(pc);
      |             ^~~
In file included from /home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:15:
/home/kamalnath/projects/malamute/moose/framework/build/header_symlinks/MoosePreconditioner.h:71:25: note: declared protected here
   71 |   NonlinearSystemBase & _nl;
      |                         ^~~
/home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:356:13: error: invalid use of incomplete type 'class NonlinearSystemBase'
  356 |         pc->_nl.setPreconditioner(pc);
      |         ~~~~^~~
In file included from /home/kamalnath/projects/malamute/moose/framework/build/header_symlinks/FEProblemBase.h:24,
                 from /home/kamalnath/projects/malamute/moose/framework/build/header_symlinks/FEProblem.h:12,
                 from /home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:13:
/home/kamalnath/projects/malamute/moose/framework/build/header_symlinks/PetscSupport.h:26:7: note: forward declaration of 'class NonlinearSystemBase'
   26 | class NonlinearSystemBase;
      |       ^~~~~~~~~~~~~~~~~~~
make: *** [/home/kamalnath/projects/malamute/moose/framework/build.mk:151: /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.x86_64-conda-linux-gnu.opt.lo] Error 1

[GiudGiud]

same need

#include "NonlinearSystemBase.h"

[KamalnathOSU]

got it. I still get one more error as shown below.

Checking if header needs updating: /home/kamalnath/projects/malamute/moose/framework/include/base/MooseRevision.h...
Checking if header needs updating: /home/kamalnath/projects/malamute/include/base/MalamuteRevision.h...
Compiling C++ (in opt mode) /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.C...
In file included from /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.C:2:
/home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C: In member function 'virtual void SetupBaseLPBF::act()':
/home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:368:10: error: 'NonlinearSystemBase& MoosePreconditioner::_nl' is protected within this context
  368 |      pc->_nl.setPreconditioner(pc);
      |          ^~~
In file included from /home/kamalnath/projects/malamute/src/actions/SetupBaseLPBF.C:15:
/home/kamalnath/projects/malamute/moose/framework/build/header_symlinks/MoosePreconditioner.h:71:25: note: declared protected here
   71 |   NonlinearSystemBase & _nl;
      |                         ^~~
make: *** [/home/kamalnath/projects/malamute/moose/framework/build.mk:151: /home/kamalnath/projects/malamute/build/unity_src/actions_Unity.x86_64-conda-linux-gnu.opt.lo] Error 1

[KamalnathOSU]

Hi @GiudGiud ,

If I use the line below, then I don't get compilation error. But what does the argument 0 mean for getNonlinearSystemBase() ?

_problem->getNonlinearSystemBase(/*nl_sys=*/0).setPreconditioner(pc);
//pc->_nl.setPreconditioner(pc);

[GiudGiud]

0 is for the index of the nonlinear system.
if you are not using multi-system, 0 is fine, you only have 1 system at index 0