feat: Split statistics components computation & output (#3836)

Allow to query statistics computation for solver (for reservoir reference pressure for wells), without needing an output statistics component. Statistics are no longer recomputed for each convergence step but only at iteration start.
- `RegionStatistics` classes for resulting data storages at different levels:
    - sub-regions mpi-local kernel compute read-backs,
    - (cell element) regions,
    - solver discretisation `MeshLevel`,
- `StatsAggregator` classes to compute & reduce the statistics to rank 0,
- `StatsTask` `Group`, the user component to schedule flow statistics computation & output to log & CSV.

Author: MelReyCG

.integrated_tests.yaml

@@ -1,6 +1,6 @@
 baselines:
   bucket: geosx
-  baseline: integratedTests/baseline_integratedTests-pr4040-16993-1393f80
+  baseline: integratedTests/baseline_integratedTests-pr3836-17046-2e89f64
 
 allow_fail:
   all: ''

BASELINE_NOTES.md

@@ -5,6 +5,10 @@ This file is designed to track changes to the integrated test baselines.
 Any developer who updates the baseline ID in the .integrated_tests.yaml file is expected to create an entry in this file with the pull request number, date, and their justification for rebaselining.
 These notes should be in reverse-chronological order, and use the following time format: (YYYY-MM-DD).
 
+PR #3836 (2026-05-20) <https://storage.googleapis.com/geosx/integratedTests/baseline_integratedTests-pr3836-17046-2e89f64.tar.gz>
+=====================
+Added statistics `Group` objects for each statistics `Task` instance
+
 PR #4040 (2026-06-16) <https://storage.googleapis.com/geosx/integratedTests/baseline_integratedTests-pr4040-16993-1393f80.tar.gz>
 Move relperm driver to use new constitutive driver framework
 

src/coreComponents/common/format/table/TableFormatter.hpp

@@ -57,6 +57,12 @@ class TableFormatter
   TableErrorListing & getErrorsList() const
   { return *m_errors; }
 
+  /**
+   * @return The prepared table layout
+   */
+  PreparedTableLayout const & getLayout() const
+  { return m_tableLayout; }
+
 protected:
 
   /// Layout for a table

src/coreComponents/common/format/table/TableTypes.hpp

@@ -82,7 +82,7 @@ class TableErrorListing
    * @brief Append a vector of string to the errors vector.
    * @param errors A vector of string to append
    */
-  void appendErrors( stdVector< string > & errors )
+  void appendErrors( stdVector< string > const & errors )
   { m_errorList.insert( m_errorList.end(), errors.begin(), errors.end() );}
 
   /**

src/coreComponents/dataRepository/DataContext.hpp

@@ -78,7 +78,7 @@ class DataContext
   /**
    * @return Get the target object name
    */
-  string getTargetName() const
+  string const & getTargetName() const
   { return m_targetName; }
   /**
    * @brief Insert contextual information in the provided stream.
@@ -179,13 +179,13 @@ class DataFileContext final : public DataContext
   /**
    * @return the type name in the source file (XML node tag name / attribute name).
    */
-  string getTypeName() const
+  string const & getTypeName() const
   { return m_typeName; }
 
   /**
    * @return the source file path where the target object has been declared.
    */
-  string getFilePath() const
+  string const & getFilePath() const
   { return m_filePath; }
 
   /**

src/coreComponents/mesh/MeshBody.hpp

@@ -96,8 +96,7 @@ class MeshBody : public dataRepository::Group
    * @param[in] level The lookup key of the MeshLevel
    * @return const reference to the MeshLevel
    */
-  template< typename T, std::enable_if_t< std::is_same< T, string >::value ||
-                                          std::is_same< T, const char * >::value, bool > = false >
+  template< typename T >
   MeshLevel & getMeshLevel( T const & level ) const
   { return m_meshLevels.getGroup< MeshLevel >( level ); }
 
@@ -108,8 +107,7 @@ class MeshBody : public dataRepository::Group
    * @param[in] level The lookup key of the MeshLevel
    * @return Reference to the MeshLevel
    */
-  template< typename T, std::enable_if_t< std::is_same< T, string >::value ||
-                                          std::is_same< T, const char * >::value, bool > = false >
+  template< typename T >
   MeshLevel & getMeshLevel( T const & level )
   { return m_meshLevels.getGroup< MeshLevel >( level ); }
 

src/coreComponents/physicsSolvers/CMakeLists.txt

@@ -29,7 +29,9 @@ set( physicsSolversBase_headers
      NonlinearSolverParameters.hpp
      PhysicsSolverBase.hpp
      PhysicsSolverBaseKernels.hpp
-     SolverStatistics.hpp )
+     SolverStatistics.hpp
+     StatisticsAggregatorBase.hpp
+     StatisticsAggregatorBaseHelpers.hpp )
 #
 # Specify solver sources
 #

src/coreComponents/physicsSolvers/FieldStatisticsBase.hpp

@@ -50,8 +50,7 @@ class FieldStatisticsBase : public TaskBase
     m_outputDir( joinPath( OutputBase::getOutputDirectory(), name ) )
   {
 
-    string const key = SOLVER::coupledSolverAttributePrefix() + "SolverName";
-    registerWrapper( key, &m_solverName ).
+    registerWrapper( getSolverWrapperKey(), &m_solverName ).
       setRTTypeName( rtTypes::CustomTypes::groupNameRef ).
       setInputFlag( dataRepository::InputFlags::REQUIRED ).
       setDescription( "Name of the " + SOLVER::coupledSolverAttributePrefix() + " solver" );
@@ -80,6 +79,20 @@ class FieldStatisticsBase : public TaskBase
 
 protected:
 
+  struct viewKeyStruct
+  {
+    static constexpr char const * writeCSVFlagString() { return "writeCSV"; }
+  };
+
+  /// Pointer to the physics solver
+  SOLVER * m_solver;
+
+  // Output directory
+  string const m_outputDir;
+
+  // Flag to enable writing CSV output
+  integer m_writeCSV;
+
   void postInputInitialization() override
   {
     Group & problemManager = this->getGroupByPath( "/Problem" );
@@ -103,19 +116,8 @@ class FieldStatisticsBase : public TaskBase
     }
   }
 
-  struct viewKeyStruct
-  {
-    static constexpr char const * writeCSVFlagString() { return "writeCSV"; }
-  };
-
-  /// Pointer to the physics solver
-  SOLVER * m_solver;
-
-  // Output directory
-  string const m_outputDir;
-
-  // Flag to enable writing CSV output
-  integer m_writeCSV;
+  string getSolverWrapperKey() const
+  { return SOLVER::coupledSolverAttributePrefix() + "SolverName"; }
 
 private: