C++ MultiBlockLattice2D::collideAndStream方法代码示例

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);
    global::directories().setOutputDir("./tmp/");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
           nx, ny, new BGKdynamics<T,DESCRIPTOR>(omega) );

    lattice.periodicity().toggleAll(true); // Set periodic boundaries.

    defineInitialDensityAtCenter(lattice);

    // First part: loop over time iterations.
    for (plint iT=0; iT<maxIter; ++iT) {
        lattice.collideAndStream();
    }

    // Second part: Data analysis.
    Array<T,2> velocity;
    lattice.get(nx/2, ny/2).computeVelocity(velocity);
    pcout << "Velocity in the middle of the lattice: ("
          << velocity[0] << "," << velocity[1] << ")" << endl;

    pcout << "Velocity norm along a horizontal line: " << endl;
    Box2D line(0, 100, ny/2, ny/2);
    pcout << setprecision(3) << *computeVelocityNorm(*extractSubDomain(lattice, line)) << endl;

    plb_ofstream ofile("profile.dat");
    ofile << setprecision(3) << *computeVelocityNorm(*extractSubDomain(lattice, line)) << endl;

    pcout << "Average density in the domain: " << computeAverageDensity(lattice) << endl;
    pcout << "Average energy in the domain: " << computeAverageEnergy(lattice) << endl;
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);
    global::directories().setOutputDir("./tmp/");

    IncomprFlowParam<T> parameters (
        (T) 1e-2,  // uMax
        (T) 10.,   // Re
        30,        // N
        2.,        // lx
        1.         // ly 
    );

    plint nx = parameters.getNx();
    plint ny = parameters.getNy();

    writeLogFile(parameters, "Poiseuille flow");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
              nx, ny,
              new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );
    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();
    createPoiseuilleBoundaries(lattice, parameters, *boundaryCondition);
    lattice.initialize();

    // The following command opens a text-file, in which the velocity-profile
    // in the middle of the channel will be written and several successive
    // time steps. Note the use of plb_ofstream instead of the standard C++
    // ofstream, which is required to guarantee a consistent behavior in MPI-
    // parallel programs.
    plb_ofstream successiveProfiles("velocityProfiles.dat");

    // Main loop over time steps.
    for (plint iT=0; iT<10000; ++iT) {
        if (iT%1000==0) {
            pcout << "At iteration step " << iT
                  << ", the density along the channel is " << endl;
            pcout << setprecision(7)
                  << *computeDensity(lattice, Box2D(0, nx-1, ny/2, ny/2))
                  << endl << endl;

            Box2D profileSection(nx/2, nx/2, 0, ny-1);
            successiveProfiles
                << setprecision(4)
                  // (2) Convert from lattice to physical units.
                << *multiply (
                       parameters.getDeltaX() / parameters.getDeltaT(),
                  // (1) Compute velocity norm along the chosen section.
                       *computeVelocityNorm (lattice, profileSection) )
                << endl;

        }

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();
    }

    delete boundaryCondition;
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    IncomprFlowParam<T> parameters(
        (T) 1e-2,  // uMax
        (T) 100.,  // Re
        64,        // N
        5.,        // lx
        1.         // ly
    );
    const T logT     = (T)0.01;
    const T imSave   = (T)0.02;
    const T maxT     = (T)1.1;

    writeLogFile(parameters, "Poiseuille flow");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
        parameters.getNx(), parameters.getNy(),
        new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );

    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
    boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();

    cylinderSetup(lattice, parameters, *boundaryCondition);

    // Main loop over time iterations.
    for (plint iT=0; iT*parameters.getDeltaT()<maxT; ++iT) {
        // At this point, the state of the lattice corresponds to the
        //   discrete time iT. However, the stored averages (getStoredAverageEnergy
        //   and getStoredAverageEnergy) correspond to the previous time iT-1.

        if (iT%parameters.nStep(imSave)==0) {
            pcout << "Saving Gif ..." << endl;
            writeGifs(lattice, iT);
        }

        if (iT%parameters.nStep(logT)==0) {
            pcout << "step " << iT
                  << "; t=" << iT*parameters.getDeltaT();
        }

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();

        // At this point, the state of the lattice corresponds to the
        //   discrete time iT+1, and the stored averages are upgraded to time iT.
        if (iT%parameters.nStep(logT)==0) {
            pcout << "; av energy ="
                  << setprecision(10) << getStoredAverageEnergy<T>(lattice)
                  << "; av rho ="
                  << getStoredAverageDensity<T>(lattice) << endl;
        }
    }
    delete boundaryCondition;
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    // Parameters of the simulation
    plint N         = 400;    // Use a 400x200 domain.
    plint maxT      = 20001;
    plint imageIter = 1000;
    T omega        = 1.;
    plint radius    = N/3;    // Inner radius of the half-circle.

    // Parameters for the creation of the multi-block.
    
    // d is the width of the block which is exempted from the full domain.
    plint d = (plint) (2.*std::sqrt((T)util::sqr(radius)-(T)util::sqr(N/4.)));
    plint x0 = (N-d)/2 + 1;  // Begin of the exempted block.
    plint x1 = (N+d)/2 - 1;  // End of the exempted block.

    // Create a block distribution with the three added blocks.
    plint envelopeWidth = 1;
    SparseBlockStructure2D sparseBlock(N+1, N/2+1);
    sparseBlock.addBlock(Box2D(0, x0,      0, N/2),   sparseBlock.nextIncrementalId());
    sparseBlock.addBlock(Box2D(x0+1, x1-1, 0, N/4+1), sparseBlock.nextIncrementalId());
    sparseBlock.addBlock(Box2D(x1, N,      0, N/2),   sparseBlock.nextIncrementalId());

    // Instantiate the multi-block, based on the created block distribution and
    // on default parameters.
    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
        MultiBlockManagement2D (
            sparseBlock,
            defaultMultiBlockPolicy2D().getThreadAttribution(), envelopeWidth ),
        defaultMultiBlockPolicy2D().getBlockCommunicator(),
        defaultMultiBlockPolicy2D().getCombinedStatistics(),
        defaultMultiBlockPolicy2D().getMultiCellAccess<T,DESCRIPTOR>(),
        new BGKdynamics<T,DESCRIPTOR>(omega)
    );

    pcout << getMultiBlockInfo(lattice) << std::endl;

    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();

    halfCircleSetup(lattice, N, radius, *boundaryCondition);

    // Main loop over time iterations.
    for (plint iT=0; iT<maxT; ++iT) {
        if (iT%imageIter==0) {
            pcout << "Saving Gif at time step " << iT << endl;
            writeGifs(lattice, iT);
        }
        lattice.collideAndStream();
    }

    delete boundaryCondition;
}

int main(int argc, char *argv[])
{
    plbInit(&argc, &argv);
    global::directories().setOutputDir("./tmp/");

    // For the choice of the parameters G, rho0, and psi0, we refer to the book
    //   Michael C. Sukop and Daniel T. Thorne (2006), 
    //   Lattice Boltzmann Modeling; an Introduction for Geoscientists and Engineers.
    //   Springer-Verlag Berlin/Heidelberg.
    
    const T omega = 1.0;
    const int nx   = 400;
    const int ny   = 400;
    const T G      = -120.0;
    const int maxIter  = 100001;
    const int saveIter = 100;
    const int statIter = 100;
    
    const T rho0 = 200.0;
    const T deltaRho = 1.0;
    const T psi0 = 4.0;

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
            nx,ny, new ExternalMomentBGKdynamics<T, DESCRIPTOR>(omega) );
            
    lattice.periodicity().toggleAll(true);

    // Use a random initial condition, to activate the phase separation.
    applyProcessingFunctional(new RandomInitializer<T,DESCRIPTOR>(rho0,deltaRho), 
                              lattice.getBoundingBox(),lattice);

    // Add the data processor which implements the Shan/Chen interaction potential.
    plint processorLevel = 1;
    integrateProcessingFunctional (
            new ShanChenSingleComponentProcessor2D<T,DESCRIPTOR> (
                G, new interparticlePotential::PsiShanChen94<T>(psi0,rho0) ),
            lattice.getBoundingBox(), lattice, processorLevel );

    lattice.initialize();
    
    pcout << "Starting simulation" << endl;
    for (int iT=0; iT<maxIter; ++iT) {
        if (iT%statIter==0) {
            auto_ptr<MultiScalarField2D<T> > rho( computeDensity(lattice) );
            pcout << iT << ": Average rho fluid one = " << computeAverage(*rho) << endl;
            pcout << "Minimum density: " << computeMin(*rho) << endl;
            pcout << "Maximum density: " << computeMax(*rho) << endl;
        }
        if (iT%saveIter == 0) {
            ImageWriter<T>("leeloo").writeScaledGif (
                    createFileName("rho", iT, 6), *computeDensity(lattice) );
        }

        lattice.collideAndStream();
    }
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    IncomprFlowParam<T> parameters(
            (T) 1e-2,  // uMax
            (T) 300.,  // Re
            100,       // N
            5.,        // lx
            1.         // ly 
    );
    const T logT     = (T)0.02;
    const T imSave   = (T)0.1;
    const T vtkSave  = (T)3.;
    const T maxT     = (T)10.1;

    writeLogFile(parameters, "Poiseuille flow");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
            parameters.getNx(), parameters.getNy(),
            new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );

    lattice.periodicity().toggle(0, false);

    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        //boundaryCondition = createInterpBoundaryCondition2D<T,DESCRIPTOR>();
        boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();

    defineCylinderGeometry(lattice, parameters);
    setupInletAndBulk(lattice, parameters, *boundaryCondition);
    //copyUnknownOnOutlet(lattice, parameters, *boundaryCondition);
    velocityNeumannOutlet(lattice, parameters, *boundaryCondition);
    lattice.initialize();

    // Main loop over time iterations.
    for (plint iT=0; iT*parameters.getDeltaT()<maxT; ++iT) {
        if ((iT+1)%parameters.nStep(logT)==0) {
            pcout << computeAverageDensity(lattice) << endl;
            pcout << computeAverageEnergy(lattice) << endl;
        }
        if (iT%parameters.nStep(logT)==0) {
            pcout << "step " << iT
                  << "; lattice time=" << lattice.getTimeCounter().getTime()
                  << "; t=" << iT*parameters.getDeltaT()
                  << "; av energy="
                  << setprecision(10) << getStoredAverageEnergy<T>(lattice)
                  << "; av rho="
                  << getStoredAverageDensity<T>(lattice) << endl;
        }

        if (iT%parameters.nStep(imSave)==0) {
            pcout << "Saving Gif ..." << endl;
            writeGifs(lattice, iT);
        }

        if (iT%parameters.nStep(vtkSave)==0 && iT>0) {
            pcout << "Saving VTK file ..." << endl;
            writeVTK(lattice, parameters, iT);
        }

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();
    }

    delete boundaryCondition;
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    IncomprFlowParam<T> parameters(
            (T) 1e-2,  // uMax
            (T) 100.,  // Re
            1024,       // N
            1.,        // lx
            1.         // ly
    );
    const T logT     = (T)0.1;
    const T imSave   = (T)0.2;
    const T vtkSave  = (T)1.;
    const T maxT     = (T)10.1;

    writeLogFile(parameters, "2D cavity");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
              parameters.getNx(), parameters.getNy(),
              new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );

    MultiBlockLattice2D<T, DESCRIPTOR> lattice2 (
              parameters.getNx(), parameters.getNy(),
              new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );

    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();

    cavitySetup(lattice, parameters, *boundaryCondition);
    cavitySetup(lattice2, parameters, *boundaryCondition);

    T previousIterationTime = T();

    MultiScalarField2D<T> rhoBar(lattice2);
    MultiTensorField2D<T,2> j(lattice2);
    std::vector<MultiBlock2D*> lattice2RhoBarJparam;
    lattice2RhoBarJparam.push_back(&lattice2);
    lattice2RhoBarJparam.push_back(&rhoBar);
    lattice2RhoBarJparam.push_back(&j);
    computeRhoBarJ(lattice2, rhoBar, j, lattice2.getBoundingBox());

    integrateProcessingFunctional( new ExternalRhoJcollideAndStream2D<T,DESCRIPTOR>,
                                   lattice2.getBoundingBox(), lattice2RhoBarJparam, -1 );
    // Main loop over time iterations.
    global::timer("iterations").start();
    for (plint iT=0; iT<1000; ++iT) {

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();
        lattice2.executeInternalProcessors(-1);
        lattice2.executeInternalProcessors();
        computeRhoBarJ(lattice2, rhoBar, j, lattice2.getBoundingBox());

        if (iT%100==0) {
            pcout << "Energy 1: " << computeAverageEnergy(lattice) << std::endl;
            pcout << "Energy 2: " << computeAverageEnergy(lattice2) << std::endl;
            pcout << global::timer("iterations").getTime()/(iT+1) << std::endl;
            //ImageWriter<T> imageWriter("leeloo");
            //imageWriter.writeScaledGif(createFileName("diff", iT, 6),
            //        //*computeVelocityNorm(lattice2) );
            //        *subtract(*computeVelocityNorm(lattice),*computeVelocityNorm(lattice2)) );
        }

    }

    delete boundaryCondition;
}

//.........这里部分代码省略.........
        pcout << "Error : Wrong parameters specified." << endl;
        pcout << "1 : N." << endl;
        exit(1);
    }

    const plint N = atoi(argv[1]);

    const T Re = 1.0;
    const T alpha = 1.0; // womersley number

    const plint Nref = 10;

    const T uMaxRef = 0.01;

    const T uMax = uMaxRef /(T)N * (T)Nref; // needed to avoid compressibility errors.

    const T lx  = 100.0;
    const T ly  = 1.0;
    pcout << "uMaxRef=" << uMaxRef << std::endl;
    pcout << "uMax=" << uMax << std::endl;

    global::directories().setOutputDir("./tmp/");

    IncomprFlowParam<T> parameters(uMax, Re, N, lx, ly);

//     The frequency of the force (lattice units)
    T frequency = (T)4*alpha*alpha*parameters.getLatticeNu()
                  / (T)(parameters.getResolution()*parameters.getResolution());

//     The amplitude of the forcing term (lattice units)
    T amplitude = 8. * parameters.getLatticeNu() * parameters.getLatticeU()
                  / ( (T)(parameters.getResolution()*parameters.getResolution()) );

//     Period of the force (lattice units)
    plint tPeriod = (plint)((T)2*pi/frequency + 0.5);

    writeLogFile(parameters,"palabos.log");

    plint nx = parameters.getNx();
    plint ny = parameters.getNy();

    T omega = parameters.getOmega();

    MultiBlockLattice2D<T, NSDESCRIPTOR> lattice (
        nx,ny,new DYNAMICS );

    OnLatticeBoundaryCondition2D<T,NSDESCRIPTOR>*
    boundaryCondition = createLocalBoundaryCondition2D<T,NSDESCRIPTOR>();

    lattice.periodicity().toggle(0,true);

    channelSetup( lattice, parameters, *boundaryCondition, alpha, frequency, amplitude);

    pcout << "Starting simulation" << endl;

    const plint maxIter = tPeriod * 100;
    //const plint tSave = tPeriod / 24;


    T error = T();

    lattice.getTimeCounter().resetTime(1);

    pcout << "Omega = " << omega << ", it period = " << tPeriod << endl;

    util::ValueTracer<T> converge(uMax,N,1.0e-3);
    plint iT = 0;
    for (iT = 0; iT < maxIter; ++iT) {
//         Updating the force in the whole domain
        Array<T,NSDESCRIPTOR<T>::d> force(womersleyForce((T)iT, amplitude, frequency, parameters),0.);
        setExternalVector(lattice,lattice.getBoundingBox(),
                          NSDESCRIPTOR<T>::ExternalField::forceBeginsAt,force);

        T errorTemp = computeRMSerror( lattice,parameters,alpha,iT);
        error += errorTemp;

        //if (iT % tSave == 0) {
        //    pcout << "Writing Gif at time : " << iT << std::endl;
        //    writeGif(lattice,iT);
        //}

        if (iT % tPeriod == 0)
        {
//             The error is averaged over one period
            error /= (T)(tPeriod);
            pcout << "For N = " << N << ", Error = " << error << endl;
            converge.takeValue(error,true);
            if (converge.hasConverged())
            {
                cout << "Simulation converged!\n";
                break;
            }
            error = T();
        }

        lattice.collideAndStream();
    }

    pcout << "For N = " << N << ", Error = " << computeRMSerror ( lattice,parameters,alpha,iT, true) << endl;
}

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");
    PlbT Re(600.,600*1e-3);
	pcout << Re.real() <<"  "<<Re.imaginary()<<endl;
	IncomprFlowParam<PlbT> parameters(
            (PlbT) 1e-2,  // uMax
            (PlbT) Re,  // Re
            100,       // N
            6.,        // lx
            1.         // ly 
    );
    const T logT     = (T)0.02;
    const T imSave   = (T)0.06;
    const T vtkSave  = (T)0.06;
    const T maxT     = (T)20.1;
	pcout<<"  " << parameters.getDeltaT().imaginary()<<endl;

    //writeLogFile(parameters, "Poiseuille flow");

    MultiBlockLattice2D<PlbT, DESCRIPTOR> lattice (
            parameters.getNx(), parameters.getNy(),
            new BGKdynamics<PlbT,DESCRIPTOR>(parameters.getOmega()) );
	pcout << parameters.getOmega().real()<<"   "<< parameters.getOmega().imaginary()<< endl;

	

    OnLatticeBoundaryCondition2D<PlbT,DESCRIPTOR>*
        boundaryCondition = createLocalBoundaryCondition2D<PlbT,DESCRIPTOR>();

    cylinderSetup(lattice, parameters, *boundaryCondition);
	
	//Array<PlbT,2> velocity;
//    lattice.get(10, 10).computeVelocity(velocity);
//    pcout << "Velocity in the middle of the lattice: ("
//	<< velocity[0].real()<<" "<<velocity[0].imaginary() << "," << velocity[1].real()<<" "<<velocity[1].imaginary()  << ")" << endl;

    // Main loop over time iterations.
    for (plint iT=0; (T)iT*parameters.getDeltaT().real()<maxT; ++iT) {
        // At this point, the state of the lattice corresponds to the
        //   discrete time iT. However, the stored averages (getStoredAverageEnergy
        //   and getStoredAverageDensity) correspond to the previous time iT-1.

       if (iT%parameters.nStep(imSave)==0) {
            //pcout << "Saving Gif ..." << endl;
            //writeGif(lattice, iT);
        }

        //if (iT%parameters.nStep(vtkSave)==0 && iT>=0) {
        //    pcout << "Saving VTK file ..." << endl;
        //    writeVTK(lattice, parameters, iT);
        //}
		if (iT%parameters.nStep(vtkSave)==0 && iT>=0) {
            pcout << "Saving VTK file ..." << endl;
            writeVTK(lattice, parameters, iT);
			Array<PlbT,2> velocity;
		    lattice.get(10, 10).computeVelocity(velocity);
			pcout << "Velocity in the middle of the lattice: ("
			      << velocity[0].real()<<" "<<velocity[0].imaginary() << "," << velocity[1].real()<<" "<<velocity[1].imaginary()  << ")" << endl;
        }

        if (iT%parameters.nStep(logT)==0) {
            pcout << "step " << iT
                  << "; t=" << (T)iT*parameters.getDeltaT().real();
        }

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();
//		lattice.get(10, 10).computeVelocity(velocity);
//		pcout << "Velocity in the middle of the lattice: ("
//		<< velocity[0].real()<<" "<<velocity[0].imaginary() << "," << velocity[1].real()<<" "<<velocity[1].imaginary()  << ")" << endl;

        // At this point, the state of the lattice corresponds to the
        //   discrete time iT+1, and the stored averages are upgraded to time iT.
        if (iT%parameters.nStep(logT)==0) {
            pcout << "; av energy ="
                  << setprecision(10) << getStoredAverageEnergy<PlbT>(lattice)
                  << "; av rho ="
                  << getStoredAverageDensity<PlbT>(lattice) << endl;
        }
    }
    
    delete boundaryCondition;
}

int main(int argc, char* argv[]) {

  /// === 1st Step: Initialization ===
  olbInit(&argc, &argv);
  singleton::directories().setOutputDir("./tmp/");
  OstreamManager clout(std::cout,"main");

  const T uMax = 0.02;
  const T Re   = 10.;
  const int N  = 50;

  const T lx   = 2.;
  const T ly   = 1.;

  const int maxIter  = 20000;

  LBconverter<T> converter(
    (int) 2,                               // dim
    1./N,                                  // latticeL_
    uMax,                                  // latticeU_
    (T)   1./Re,                           // charNu_
    (T)   1.                               // charL_ = 1,
  );
  writeLogFile(converter, "poiseuille2d");

  /// === 3rd Step: Prepare Lattice ===

#ifndef PARALLEL_MODE_MPI  // sequential program execution
  BlockLattice2D<T, DESCRIPTOR> lattice(converter.numNodes(lx), converter.numNodes(ly) );
#else                      // parallel program execution
  MultiBlockLattice2D<T, DESCRIPTOR> lattice (
    createRegularDataDistribution( converter.numNodes(lx), converter.numNodes(ly) ) );
#endif


  // choose between local and non-local boundary condition
  OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
  boundaryCondition = createInterpBoundaryCondition2D(lattice);
  // boundaryCondition = createLocalBoundaryCondition2D(lattice);

  ForcedBGKdynamics<T, DESCRIPTOR> bulkDynamics (
    converter.getOmega(),
    instances::getBulkMomenta<T,DESCRIPTOR>()
  );

  prepareLattice(converter, lattice, bulkDynamics, *boundaryCondition);

  /// === 4th Step: Main Loop with Timer ===

  for (int iT=0; iT<maxIter; ++iT) {
    
    /// === 5th Step: Definition of Initial and Boundary Conditions ===
    setBoundaryValues(converter, lattice, iT);


    /// === 6th Step: Collide and Stream Execution ===
    lattice.collideAndStream(true);

    /// === 7th Step: Computation and Output of the Results ===
    getResults(lattice, converter, iT);
  }

  delete boundaryCondition;
}

int main(int argc, char* argv[]) {

    /// === 1st Step: Initialization ===

  olbInit(&argc, &argv);
  OstreamManager clout(std::cout,"main");

  string fName("cavity2d.xml");
  XMLreader config(fName);

  bool multiOutput=false;
  config["Output"]["MultiOutput"].read(multiOutput);
  clout.setMultiOutput(multiOutput);

  std::string olbdir, outputdir;
  config["Application"]["OlbDir"].read(olbdir);
  config["Output"]["OutputDir"].read(outputdir);
  singleton::directories().setOlbDir(olbdir);
  singleton::directories().setOutputDir(outputdir);

// call creator functions using xml data
  LBconverter<T>* converter = createLBconverter<T>(config);
  int N = converter->numNodes();
  Timer<T>* timer           = createTimer<T>(config, *converter, N*N);

/// === 3rd Step: Prepare Lattice ===

  T logT;
  T imSave;
  T vtkSave;
  T maxT;
  int timerSkipType;
  bool timerPrintSum = true;
  int timerPrintMode = 0;
  int timerTimeSteps = 1;

  config["Application"]["PhysParam"]["MaxTime"].read(maxT);
  config["Output"]["Log"]["SaveTime"].read(logT);
  config["Output"]["VisualizationImages"]["SaveTime"].read(imSave);
  config["Output"]["VisualizationVTK"]["SaveTime"].read(vtkSave);
  config["Output"]["Timer"]["SkipType"].read(timerSkipType);
  config["Output"]["Timer"]["PrintSummary"].read(timerPrintSum);
  config["Output"]["Timer"]["PrintMode"].read(timerPrintMode);

  if (timerSkipType == 0) {
    timerTimeSteps=converter->numTimeSteps(config["Output"]["Timer"]["PhysTime"].get<T>());
  } else {
    config["Output"]["Timer"]["TimeSteps"].read(timerTimeSteps);
  }

  writeLogFile(*converter, config["Output"]["Log"]["Filename"].get<std::string>());

  std::string filenameGif = config["Output"]["VisualizationImages"]["Filename"].get<std::string>();

  std::string filenameVtk = config["Output"]["VisualizationVTK"]["Filename"].get<std::string>();

#ifndef PARALLEL_MODE_MPI  // sequential program execution
  BlockLattice2D<T, DESCRIPTOR> lattice(N, N);
#else                      // parallel program execution
  MultiBlockLattice2D<T, DESCRIPTOR> lattice (
    createRegularDataDistribution(N, N) );
#endif

  ConstRhoBGKdynamics<T, DESCRIPTOR> bulkDynamics (
    converter->getOmega(),
    instances::getBulkMomenta<T,DESCRIPTOR>()
  );

  OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
  boundaryCondition = createInterpBoundaryCondition2D(lattice);

  prepareLattice(converter, lattice, bulkDynamics, *boundaryCondition);

    /// === 4th Step: Main Loop with Timer ===

  timer->start();

  int iT=0;
  for (iT=0; converter->physTime(iT)<maxT; ++iT) {
    

    /// === 5th Step: Definition of Initial and Boundary Conditions ===
    setBoundaryValues(converter, lattice, iT);

    /// === 6th Step: Collide and Stream Execution ===
    lattice.collideAndStream();

    /// === 7th Step: Computation and Output of the Results ===
    getResults(lattice, converter, iT, timer, logT, imSave, vtkSave, maxT, filenameGif, filenameVtk,
               timerPrintSum, timerPrintMode, timerTimeSteps);
   

  }


  delete converter;
  delete timer;
  delete boundaryCondition;

  return 0;
//.........这里部分代码省略.........

int main(int argc, char* argv[]) {
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    T    Re; // Reynolds number.
    plint N;  // Resolution.

    //getParametersFromCommandLine(argc, argv, Re, N);
    getParametersFromParamFile(Re, N);

    IncomprFlowParam<T> parameters(
            (T) 1e-2,  // uMax
            (T) 100.,  // Re
            128,        // N
            1.,        // lx
            1.         // ly 
    );
    const T logT     = (T)0.1;
    const T imSave   = (T)0.2;
    const T maxT     = (T)10.1;

    writeLogFile(parameters, "2D cavity");

    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
              parameters.getNx(), parameters.getNy(),
              new BGKdynamics<T,DESCRIPTOR>(parameters.getOmega()) );

    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        //boundaryCondition = createInterpBoundaryCondition2D<T,DESCRIPTOR>();
        boundaryCondition = createLocalBoundaryCondition2D<T,DESCRIPTOR>();

    cavitySetup(lattice, parameters, *boundaryCondition);

    // Main loop over time iterations.
    for (plint iT=0; iT*parameters.getDeltaT()<maxT; ++iT) {
        if ((iT+1)%parameters.nStep(logT)==0) {
            pcout << computeAverageDensity(lattice) << endl;
            pcout << computeAverageEnergy(lattice) << endl;
        }
        if (iT%parameters.nStep(logT)==0) {
            pcout << "step " << iT
                  << "; lattice time=" << lattice.getTimeCounter().getTime()
                  << "; t=" << iT*parameters.getDeltaT()
                  << "; av energy="
                  << setprecision(10) << getStoredAverageEnergy<T>(lattice)
                   << "; av rho="
                 << getStoredAverageDensity<T>(lattice) << endl;
        }

        if (iT%parameters.nStep(imSave)==0 && iT>0) {
            pcout << "Saving Gif ..." << endl;
            writeGifs(lattice, iT);
            pcout << endl;
        }

        // Lattice Boltzmann iteration step.
        lattice.collideAndStream();
    }

    delete boundaryCondition;
}