.. _managers_dev: Managers in NEST ================ At the heart of NEST are various managers, each responsible for specific aspects of the simulation process. The ManagerInterface provides a common interface for all managers, defining standard methods and properties. The KernelManager acts as the core, coordinating the other managers that specialize in different aspects of the simulation. :ref:`KernelManager ` initializes all managers in dependency order: - :ref:`nest::LoggingManager ` - :ref:`nest::MPIManager ` - :ref:`nest::VPManager ` - :ref:`nest::ModuleManager ` - :ref:`nest::RandomManager ` - :ref:`nest::SimulationManager ` - :ref:`nest::ModelRangeManager ` - :ref:`nest::ConnectionManager ` - :ref:`nest::SPManager ` - :ref:`nest::EventDeliveryManager` - :ref:`nest::IOManager ` - :ref:`nest::ModelManager ` - :ref:`nest::MUSICManager ` - :ref:`nest::NodeManager ` Main control flow ----------------- 1. **Initialization**: - The Kernel Manager initializes the simulation environment, allocating resources and setting up initial configurations. - The Simulation Manager sets up the simulation based on defined parameters. 2. **Node and Connection Setup**: - The Node Manager creates and configures nodes. - The Connection Manager establishes connections between nodes. 3. **Model Application**: - The Model Manager loads and applies models to nodes and connections. - The SP Manager applies synaptic plasticity rules as needed. 4. **Simulation Execution**: - The Simulation Manager oversees the execution phase, with the Event Delivery Manager ensuring events are processed correctly. - The MPI Manager handles parallel processing tasks if the simulation is distributed. 5. **Data Handling**: - The IO Manager reads configuration files and writes simulation results. - The Logging Manager captures diagnostic information for debugging. 6. **Cleanup**: - The Simulation Manager ensures resources are cleaned up after the simulation completes. Advanced Architectural Features ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - **Policy-based template pattern for manager customization**: - The policy-based template pattern is used to customize specific manager behaviors, allowing developers to extend functionality without modifying core logic. - **Thread-local storage for performance-critical components**: - Thread-local storage is employed for performance-critical components to minimize contention and improve parallel execution efficiency. - **Double dispatch pattern for event handling**: - The double dispatch pattern is used for event handling, enabling dynamic and type-safe event processing across different node and connection types. - **MPI-agnostic interfaces through manager abstraction**: - MPI-agnostic interfaces are provided through manager abstraction, allowing the simulation to run seamlessly with or without MPI, enhancing flexibility and portability. - **Multiple synchronization strategies**: - **MPI_Barrier** is used for global synchronization to ensure all processes reach a certain point before proceeding. - **OpenMP locks** are employed for shared memory parallelism to manage access to shared resources. - **Atomic operations** are used for spike counter updates to ensure thread-safe increments without locks. - **RAII patterns** are used for resource management to ensure proper acquisition and release of resources. .. toctree:: :hidden: connection_manager event_delivery_manager io_manager mpi_manager node_manager music_manager random_manager sp_manager vp_manager logging_manager kernel_manager module_manager modelrange_manager simulation_manager model_manager