add a function to retrieve the current last mesh generator for actions …

…idaholab#15121

framework/doc/content/source/actions/Action.md

@@ -1 +1,14 @@
 # MOOSE Action System
+
+MOOSE actions, derived from the base class *Action* are used to set up a problem with other MOOSE objects including mesh generators, kernels, materials, user objects, etc.
+An action can be optionally linked to an input syntax, which provides the valid parameters to the action through the MOOSE input parser behind the scene.
+An action is assocated with tasks, which determine when the action is to be acted, or the *act* function of an action is to be called by MOOSE.
+Association with multiple tasks is allowed. In such case, it is developers' responsibility to switch the functions based on the current task in the act function.
+A full list of tasks is available in Moose.C file.
+Developers are allowed to register new tasks with MOOSE Action system.
+When actions are built either through the input parser or internally by MOOSE, they will exist during the entire simulation.
+
+MOOSE has lots of built-in actions for adding individual objects through input files.
+But MOOSE action system is far beyond the basic capabilities provided by these built-in actions.
+Developers are encouraged to explore the MOOSE actions system to create their own actions in order to perform problem setup in one place and potentially simplify the input syntax significantly.
+One example is to use an action to append a mesh generator that generats a boundary surrounding a particular subdomain for imposing specific boundary conditions, based on the information not necessarily inside of a mesh generator block.

framework/include/base/MooseApp.h

@@ -652,6 +652,11 @@ class MooseApp : public ConsoleStreamInterface, public libMesh::ParallelObject
    */
   void clearMeshGenerators();
 
+  /**
+   * Get the current final mesh generator regardless what users set in the input
+   */
+  std::string getCurrentFinalMeshGenerator() const;
+
   /**
    * Execute and clear the Mesh Generators data structure
    */

framework/include/interfaces/Coupleable.h

@@ -79,7 +79,7 @@ class Coupleable
    * Get the list of array coupled variables
    * @return The list of array coupled variables
    */
-  const std::vector<ArrayMooseVariable *> & getCoupledArratMooseVars() const
+  const std::vector<ArrayMooseVariable *> & getCoupledArrayMooseVars() const
   {
     return _coupled_array_moose_vars;
   }

framework/src/base/Moose.C

@@ -102,6 +102,7 @@ addActionTypes(Syntax & syntax)
   registerMooseObjectTask("init_mesh",                    MooseMesh,              false);
   registerMooseObjectTask("add_mesh_modifier",            MeshModifier,           false);
   registerMooseObjectTask("add_mesh_generator",           MeshGenerator,          false);
+  registerMooseObjectTask("append_mesh_generator",        MeshGenerator,          false);
 
   registerMooseObjectTask("add_kernel",                   Kernel,                 false);
   appendMooseObjectTask  ("add_kernel",                   EigenKernel);
@@ -244,6 +245,7 @@ addActionTypes(Syntax & syntax)
                            "(setup_recover_file_base)"
                            "(setup_mesh)"
                            "(add_mesh_generator)"
+                           "(append_mesh_generator)"
                            "(execute_mesh_generators)"
                            "(recover_meta_data)"
                            "(set_mesh_base)"

framework/src/base/MooseApp.C

@@ -1572,6 +1572,35 @@ MooseApp::getMeshGeneratorOutput(const std::string & name)
   return outputs.back();
 }
 
+std::string
+MooseApp::getCurrentFinalMeshGenerator() const
+{
+  DependencyResolver<std::shared_ptr<MeshGenerator>> resolver;
+
+  // Add all of the dependencies into the resolver and sort them
+  for (const auto & it : _mesh_generators)
+  {
+    // Make sure an item with no dependencies comes out too!
+    resolver.addItem(it.second);
+
+    std::vector<std::string> & generators = it.second->getDependencies();
+    for (const auto & depend_name : generators)
+    {
+      auto depend_it = _mesh_generators.find(depend_name);
+      if (depend_it != _mesh_generators.end())
+        resolver.insertDependency(it.second, depend_it->second);
+    }
+  }
+
+  const auto & ordered_generators = resolver.getSortedValuesSets();
+
+  std::string final_generator_name;
+  if (ordered_generators.size())
+    final_generator_name = ordered_generators.back().back()->name();
+
+  return final_generator_name;
+}
+
 void
 MooseApp::executeMeshGenerators()
 {

test/doc/remove.yml

@@ -1,3 +1,4 @@
+- /ModifyMesh
 - /BadKernels
 - /MoreAuxVariables
 - /Kernels/OldNamedKernel

test/include/actions/AppendMeshGeneratorAction.h

@@ -0,0 +1,28 @@
+//* This file is part of the MOOSE framework
+//* https://www.mooseframework.org
+//*
+//* All rights reserved, see COPYRIGHT for full restrictions
+//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
+//*
+//* Licensed under LGPL 2.1, please see LICENSE for details
+//* https://www.gnu.org/licenses/lgpl-2.1.html
+
+#pragma once
+
+#include "MooseObjectAction.h"
+
+// Forward Declaration
+class AppendMeshGeneratorAction;
+
+template <>
+InputParameters validParams<AppendMeshGeneratorAction>();
+
+class AppendMeshGeneratorAction : public MooseObjectAction
+{
+public:
+  static InputParameters validParams();
+
+  AppendMeshGeneratorAction(InputParameters params);
+
+  virtual void act() override;
+};

test/src/actions/AppendMeshGeneratorAction.C

@@ -0,0 +1,43 @@
+//* This file is part of the MOOSE framework
+//* https://www.mooseframework.org
+//*
+//* All rights reserved, see COPYRIGHT for full restrictions
+//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
+//*
+//* Licensed under LGPL 2.1, please see LICENSE for details
+//* https://www.gnu.org/licenses/lgpl-2.1.html
+
+#include "AppendMeshGeneratorAction.h"
+#include "MooseMesh.h"
+#include "MeshGenerator.h"
+#include "Factory.h"
+#include "MooseApp.h"
+
+registerMooseAction("MooseApp", AppendMeshGeneratorAction, "append_mesh_generator");
+
+defineLegacyParams(AppendMeshGeneratorAction);
+
+InputParameters
+AppendMeshGeneratorAction::validParams()
+{
+  InputParameters params = MooseObjectAction::validParams();
+  return params;
+}
+
+AppendMeshGeneratorAction::AppendMeshGeneratorAction(InputParameters params)
+  : MooseObjectAction(params)
+{
+}
+
+void
+AppendMeshGeneratorAction::act()
+{
+  if (!_mesh)
+    mooseError("No mesh file was supplied and no generation block was provided");
+
+  if (!_moose_object_pars.have_parameter<MeshGeneratorName>("input"))
+    mooseError("Cannot append a mesh generator that does not take input mesh generators");
+
+  _moose_object_pars.set<MeshGeneratorName>("input") = _app.getCurrentFinalMeshGenerator();
+  _app.addMeshGenerator(_type, _name, _moose_object_pars);
+}

test/src/base/MooseTestApp.C

@@ -82,6 +82,7 @@ MooseTestApp::registerAll(Factory & f, ActionFactory & af, Syntax & s, bool use_
     registerSyntax("CreateSpecialProblemAction", "TestProblem");
     registerSyntax("AddDGDiffusion", "DGDiffusionAction");
     registerSyntax("MeshMetaDataDependenceAction", "AutoLineSamplerTest");
+    registerSyntax("AppendMeshGeneratorAction", "ModifyMesh/*");
   }
 }
 

test/tests/meshgenerators/append_mesh_generator/append_mesh_generator.i

@@ -0,0 +1,20 @@
+[Mesh]
+  [gmg]
+    type = GeneratedMeshGenerator
+    dim = 2
+    nx = 3
+    ny = 3
+  []
+[]
+
+[ModifyMesh]
+  [addss]
+    type = SideSetsAroundSubdomainGenerator
+    new_boundary = whole
+    block = 0
+  []
+[]
+
+[Outputs]
+  exodus = true
+[]

test/tests/meshgenerators/append_mesh_generator/tests

@@ -0,0 +1,13 @@
+[Tests]
+  [./append_mesh_generator_test]
+    type = 'Exodiff'
+    input = 'append_mesh_generator.i'
+    cli_args = '--mesh-only'
+    exodiff = 'append_mesh_generator_in.e'
+    requirement = 'MOOSE shall be able to allow actions to append mesh generators.'
+    design = 'actions/Action.md'
+    issues = '#15121'
+    mesh_mode = 'REPLICATED'
+    recover = false
+  [../]
+[]