picsolver.c

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/**
 * @file main.c
 * @brief Main driver for the unified CFD and Lagrangian particle solver.
 *
 * This version focuses on establishing the core architecture for a particle-coupled
 * flow simulation. It initializes the grid, solver objects, and a DMSwarm of
 * Lagrangian particles. Hooks for the Immersed Boundary Method (IBM) are present
 * but are currently inactive to allow for iterative development.
 *
 * ARCHITECTURE:
 * 1. A central `SimulationContext` (simCtx) holds all simulation-wide configuration.
 * 2. `CreateSimulationContext()` handles all command-line parsing.
 * 3. The `main()` function provides a high-level workflow for the simulation.
 */
 
#include "simulation.h" // The new, unified header file
 
/*================================================================================*
 *                           MAIN FUNCTION                                        *
 *================================================================================*/
 
#undef __FUNCT__
#define __FUNCT__ "main"
int main(int argc, char **argv)
{
    PetscErrorCode    ierr;
    SimCtx *simCtx = NULL; // The single, top-level context object
 
    // === I. INITIALIZE =======================================================
    ierr = PetscInitialize(&argc, &argv, (char *)0, "PIC-Solver"); CHKERRQ(ierr);
 
    // === II. CONFIGURE =======================================================
    // Create and populate the entire simulation configuration from command line.
    ierr = CreateSimulationContext(argc, argv, &simCtx); CHKERRQ(ierr);
    // == IIB. SET EXECUTION MODE (SOLVER vs POST-PROCESSOR) =====
    simCtx->exec_mode = EXEC_MODE_SOLVER;
    
    // === III. SETUP ==========================================================
    // Build the simulation environment step-by-step.
 
    // 1. Setup the multi-grid hierarchy, DMs, and PETSc vectors/solvers.
    ierr = SetupGridAndSolvers(simCtx); CHKERRQ(ierr);
 
    // 2. Setup the boundary condition handlers for the flow solver.
    ierr = SetupBoundaryConditions(simCtx); CHKERRQ(ierr);
 
    // 3. Setup domain decomposition info needed for particle migration.
    ierr = SetupDomainRankInfo(simCtx); CHKERRQ(ierr);
 
    // 4. Setup Initial State of Eulerian Fields
    ierr = InitializeEulerianState(simCtx); CHKERRQ(ierr);
 
    // 5. If requested, initialize the Lagrangian Particle Swarm.
    if (simCtx->np > 0) {
      ierr = InitializeParticleSwarm(simCtx); CHKERRQ(ierr);
     }
 
    LOG_ALLOW(GLOBAL,LOG_INFO," Setup Completed.\n");
    
    
    /*
     * --- IBM/FSI FEATURE HOOK (Currently Inactive) ---
     * The logic for initializing immersed bodies would be enabled here.
     * The `-immersed` command-line flag would control this block.
     *
    if (simCtx->immersed) {
        ierr = InitializeImmersedBoundary(simCtx); CHKERRQ(ierr);
    }
    */
 
    // === IV. EXECUTE =========================================================
    // Display a summary banner and run the main time-stepping loop.
 
    ierr = DisplayBanner(simCtx); CHKERRQ(ierr);
 
    if (!simCtx->OnlySetup) {
        // This function will contain the main time loop, orchestrating
        // the flow solve and particle advection steps.
 
      if(simCtx->StartStep == 0){
         if(simCtx->np>0){
    ierr = PerformInitialSetup(simCtx); CHKERRQ(ierr);
        }
      }else{
    
    // Restart logic
        LOG_ALLOW(GLOBAL,LOG_INFO," Restart from Time step %d.\n",simCtx->StartStep);
      }
 
      if(simCtx->StepsToRun > 0){
     ierr = AdvanceSimulation(simCtx); CHKERRQ(ierr);
      }else{
    LOG_ALLOW(GLOBAL,LOG_INFO,"Initial setup complete.No steps to run.Exiting!.\n");
      }
 
    }else{
      LOG_ALLOW(GLOBAL,LOG_INFO,"SETUP ONLY MODE enabled. Skipping time loop.\n");
    }
 
    // === V. FINALIZE =========================================================
    // Cleanly destroy all objects and free all memory.
 
    ierr = ProfilingFinalize(); CHKERRQ(ierr);
    // ierr = FinalizeSimulation(simCtx); CHKERRQ(ierr);
    ierr = PetscFinalize();
 
    return ierr;
}