bubble-dynamics

Spherical bubble dynamics simulator
git clone https://git.0xfab.ch/bubble-dynamics.git
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RPCluster.h (6799B)


      1 /* File:   RPCluster.h */
      2 /* Date:   Sun Feb 05 22:10:34 2017 */
      3 /* Author: Ursula Rasthofer */
      4 /* Tag:    Bubble cluster based on Rayleigh-Plesset */
      5 /* Copyright 2017 ETH Zurich. All Rights Reserved. */
      6 #ifndef RPCLUSTER_H_67YUOP08
      7 #define RPCLUSTER_H_67YUOP08
      8 
      9 #include "BubbleBase.h"
     10 
     11 #include <ODETB/GnuplotDump.h>
     12 #include <ODETB/TimeStepper/KernelBase.h>
     13 
     14 #include <Eigen/Core>
     15 #include <Eigen/Dense>
     16 
     17 #include <cassert>
     18 #include <cstdlib>
     19 #include <fstream>
     20 #include <cmath>
     21 #include <vector>
     22 
     23 
     24 template <typename Tinput, typename Trhs=Tinput>
     25 class RPCluster : public KernelBase<Tinput,Trhs>
     26 {
     27     const size_t _N;
     28     GnuplotDump* m_dumper;
     29 
     30 public:
     31     RPCluster(const size_t N=0, const int format=GnuplotDump::BIN) : _N(N) { m_dumper = new GnuplotDump("out", format); }
     32     virtual ~RPCluster() { delete m_dumper;}
     33 
     34     static void IC(Tinput& U, BubbleData& data)
     35     {
     36         assert(Tinput::DataType::SIZE == 2);
     37         assert(data.Nbubbles == U.size());
     38         const size_t N = data.Nbubbles;
     39 
     40         // read IC from file
     41         std::ifstream infile(data.filename);
     42         size_t k;
     43         infile >> k;
     44         if (N != k)
     45         {
     46             std::cerr << "RPCluster: Allocated " << N << " bubbles."<< std::endl;
     47             std::cerr << "              File " << data.filename << " expects " << k << " bubbles."<< std::endl;
     48             abort();
     49         }
     50 
     51         for (size_t i = 0; i < N; ++i)
     52         {
     53             if (infile.good())
     54             {
     55                 Bubble& b = data.coords[i];
     56                 infile >> b.pos[0] >> b.pos[1] >> b.pos[2];
     57                 infile >> data.R0[i];
     58                 infile >> data.Rdot0[i];
     59 
     60                 typename Tinput::DataType& IC = U[i];
     61                 IC[0] = data.R0[i];
     62                 IC[1] = data.Rdot0[i];
     63             }
     64             else
     65             {
     66                 std::cerr << "RPCluster: Input file has incorrect format" << std::endl;
     67                 abort();
     68             }
     69         }
     70 
     71         for (size_t i = 0; i < N; ++i) {
     72             const Bubble& bi = data.coords[i];
     73             for (size_t j = 0; j < N; ++j) {
     74                 const Bubble& bj = data.coords[j];
     75                 data.Dij[j + i*N] = bi.distance(bj);
     76             }
     77         }
     78 
     79 #ifndef NDEBUG
     80         for (size_t i = 0; i < N; ++i)
     81             assert(0 == data.Dij[i + i*N]);
     82 #endif /* NDEBUG */
     83     }
     84 
     85     virtual void compute(const Tinput& U, Trhs& rhs, Real const t, void const* const data=nullptr)
     86     {
     87         const BubbleData& bd = *(BubbleData const* const)data;
     88 
     89         assert(_N == U.size());
     90         Eigen::Matrix<Real, Eigen::Dynamic, Eigen::Dynamic> A(_N,_N);
     91         Eigen::Matrix<Real, Eigen::Dynamic, 1> b(_N);
     92 
     93         for (size_t i = 0; i < _N; ++i)
     94         {
     95             const typename Tinput::DataType& Ui = U[i];
     96             // fill row i of A
     97             Real bnbr = 0;
     98             for (size_t j = 0; j < _N; ++j)
     99             {
    100                 const typename Tinput::DataType& Uj = U[j];
    101                 if (i == j)
    102                     A(i,j) = Ui[0];
    103                 else
    104                 {
    105                     const Real UDij = Uj[0]/bd.Dij[j + i*_N];
    106                     A(i,j) = Uj[0]*UDij;
    107                     bnbr += Uj[1]*Uj[1]*UDij;
    108                 }
    109             }
    110 
    111             // compute bi
    112             const Real pstat = bd.p0 - bd.pv;
    113             const Real pbs = (pstat + static_cast<Real>(2.0)*bd.sigma/bd.R0[i])*std::pow(bd.R0[i]/Ui[0], 3.0*bd.gamma);
    114 
    115             b(i) = 0.0;
    116             b(i) -= static_cast<Real>(1.5)*Ui[1]*Ui[1];
    117             b(i) -= bd.rInv*(pstat + bd.pext(t));
    118             b(i) += bd.rInv*(pbs - static_cast<Real>(2.0)*bd.sigma/Ui[0]) - static_cast<Real>(4.0)*bd.nuL*Ui[1]/Ui[0];
    119             b(i) -= static_cast<Real>(2.0)*bnbr;
    120 
    121             assert(!isnan(b(i)));
    122         }
    123 
    124         /* std::cout << A << std::endl << std::endl; */
    125         //Eigen::Matrix<Real, Eigen::Dynamic, 1> Rddot = A.fullPivHouseholderQr().solve(b);
    126         // this is notably faster and sufficiently accurate (rasthofer Feb 3, 2017)
    127         Eigen::Matrix<Real, Eigen::Dynamic, 1> Rddot = A.colPivHouseholderQr().solve(b);
    128 
    129         for (size_t i = 0; i < _N; ++i)
    130         {
    131             const typename Tinput::DataType& Ui = U[i];
    132             typename Trhs::DataType& ri = rhs[i];
    133             ri[0] = Ui[1];
    134             ri[1] = Rddot(i);
    135         }
    136     }
    137 
    138     virtual void write(const size_t step, const Real t, const Real dt, const Tinput& U, const void * const data=nullptr)
    139     {
    140         static size_t callCount = 0;
    141 
    142         const BubbleData& bd = *(BubbleData const* const)data;
    143 
    144         // double pb[3];
    145         // const int id[3] = {0, 7, 1};
    146         // for (int i = 0; i < 3; ++i)
    147         //     pb[i] = bd.pBubble(U, id[i]);
    148 
    149         // // class 1, 2, 3, 4, 5, 6
    150         // // const Real odat[6] = {U[0][0], U[1][0], U[4][0], U[2][0], U[5][0], U[3][0]};
    151         // const Real odat[7] = {U[0][0], U[7][0], U[1][0], pb[0], pb[1], pb[2], bd.pext(t)};
    152 
    153         const size_t N = 2*_N+2;
    154         std::vector<double> out(N);
    155         double Vg = 0.0;
    156         for (size_t i = 0; i < _N; ++i) {
    157             const double r = U[i][0];
    158             out[i] = r;
    159             out[i+_N] = bd.pBubble(U, i);
    160             Vg += 4.0/3.0*r*r*r*M_PI;
    161         }
    162         out[2*_N] = bd.pext(t);
    163         out[2*_N+1] = Vg;
    164 
    165         m_dumper->write(step, t, dt, out.data(), N);
    166 
    167         if (bd.bVTK)
    168         {
    169             // dump bubble vtk
    170             std::stringstream streamer;
    171             streamer<< "bubbles-vtk_" << setfill('0') << setw(8) << callCount++ << ".vtk";
    172             std::ofstream vtk(streamer.str().c_str());
    173             vtk.setf(std::ios::scientific, std::ios::floatfield);
    174 
    175             vtk << "# vtk DataFile Version 2.0\n";
    176             vtk << "Unstructured grid legacy vtk file with point scalar data\n";
    177             vtk << "ASCII\n" << std::endl;
    178 
    179             vtk << "DATASET UNSTRUCTURED_GRID\n";
    180             vtk << "POINTS " << bd.Nbubbles << " double" << std::endl;
    181             for (size_t i = 0; i < bd.Nbubbles; ++i)
    182                 vtk << bd.coords[i].pos[0] << " " << bd.coords[i].pos[1] << " " << bd.coords[i].pos[2] << std::endl;
    183             vtk << std::endl;
    184 
    185             vtk << "POINT_DATA " << bd.Nbubbles << std::endl;
    186             vtk << "SCALARS radius double\n";
    187             vtk << "LOOKUP_TABLE default" << std::endl;
    188             for (size_t i = 0; i < bd.Nbubbles; ++i)
    189                 vtk << U[i][0] << std::endl;
    190             vtk << std::endl;
    191 
    192             // vtk << "POINT_DATA " << bd.Nbubbles << std::endl;
    193             vtk << "SCALARS velocity double\n";
    194             vtk << "LOOKUP_TABLE default" << std::endl;
    195             for (size_t i = 0; i < bd.Nbubbles; ++i)
    196                 vtk << U[i][1] << std::endl;
    197             vtk << std::endl;
    198         }
    199     }
    200 };
    201 
    202 #endif /* RPCLUSTER_H_67YUOP08 */