Fluctuations.cpp

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/*
 * This file is part of Vlasiator.
 * Copyright 2010-2016 Finnish Meteorological Institute
 *
 * For details of usage, see the COPYING file and read the "Rules of the Road"
 * at http://www.physics.helsinki.fi/vlasiator/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <cmath>
 
#include "../../common.h"
#include "../../readparameters.h"
#include "../../object_wrapper.h"
#include "../../velocity_mesh_parameters.h"
#include "../../backgroundfield/backgroundfield.h"
#include "../../backgroundfield/constantfield.hpp"
 
#include "Fluctuations.h"
 
using namespace spatial_cell;
 
Real projects::Fluctuations::rndRho, projects::Fluctuations::rndVel[3];
 
 
namespace projects {
   Fluctuations::Fluctuations(): TriAxisSearch() { }
   Fluctuations::~Fluctuations() { }
   bool Fluctuations::initialize(void) {return Project::initialize();}
 
   void Fluctuations::addParameters() {
      typedef Readparameters RP;
      RP::add("Fluctuations.BX0", "Background field value (T)", 1.0e-9);
      RP::add("Fluctuations.BY0", "Background field value (T)", 2.0e-9);
      RP::add("Fluctuations.BZ0", "Background field value (T)", 3.0e-9);
      RP::add("Fluctuations.magXPertAbsAmp", "Amplitude of the magnetic perturbation along x", 1.0e-9);
      RP::add("Fluctuations.magYPertAbsAmp", "Amplitude of the magnetic perturbation along y", 1.0e-9);
      RP::add("Fluctuations.magZPertAbsAmp", "Amplitude of the magnetic perturbation along z", 1.0e-9);
 
      // Per-population parameters
      for(uint i=0; i< getObjectWrapper().particleSpecies.size(); i++) {
         const std::string& pop = getObjectWrapper().particleSpecies[i].name;
 
         RP::add(pop + "_Fluctuations.rho", "Number density (m^-3)", 1.0e7);
         RP::add(pop + "_Fluctuations.TemperatureX", "Temperature (K)", 2.0e6);
         RP::add(pop + "_Fluctuations.TemperatureY", "Temperature (K)", 2.0e6);
         RP::add(pop + "_Fluctuations.TemperatureZ", "Temperature (K)", 2.0e6);
         RP::add(pop + "_Fluctuations.densityPertRelAmp", "Amplitude factor of the density perturbation", 0.1);
         RP::add(pop + "_Fluctuations.velocityPertAbsAmp", "Amplitude of the velocity perturbation", 1.0e6);
         RP::add(pop + "_Fluctuations.maxwCutoff", "Cutoff for the maxwellian distribution", 1e-12);
      }
   }
 
   void Fluctuations::getParameters() {
      Project::getParameters();
      typedef Readparameters RP;
      Project::getParameters();
      RP::get("Fluctuations.BX0", this->BX0);
      RP::get("Fluctuations.BY0", this->BY0);
      RP::get("Fluctuations.BZ0", this->BZ0);
      RP::get("Fluctuations.magXPertAbsAmp", this->magXPertAbsAmp);
      RP::get("Fluctuations.magYPertAbsAmp", this->magYPertAbsAmp);
      RP::get("Fluctuations.magZPertAbsAmp", this->magZPertAbsAmp);
 
      // Per-population parameters
      for(uint i=0; i< getObjectWrapper().particleSpecies.size(); i++) {
         const std::string& pop = getObjectWrapper().particleSpecies[i].name;
         FluctuationsSpeciesParameters sP;
         RP::get(pop + "_Fluctuations.rho", sP.DENSITY);
         RP::get(pop + "_Fluctuations.TemperatureX", sP.TEMPERATUREX);
         RP::get(pop + "_Fluctuations.TemperatureY", sP.TEMPERATUREY);
         RP::get(pop + "_Fluctuations.TemperatureZ", sP.TEMPERATUREZ);
         RP::get(pop + "_Fluctuations.densityPertRelAmp", sP.densityPertRelAmp);
         RP::get(pop + "_Fluctuations.velocityPertAbsAmp", sP.velocityPertAbsAmp);
         RP::get(pop + "_Fluctuations.maxwCutoff", sP.maxwCutoff);
 
         speciesParams.push_back(sP);
      }
   }
 
   Realf Fluctuations::fillPhaseSpace(spatial_cell::SpatialCell *cell,
                                       const uint popID,
                                       const uint nRequested
      ) const {
      const FluctuationsSpeciesParameters& sP = speciesParams[popID];
      // Fetch spatial cell center coordinates
      // const Real x  = cell->parameters[CellParams::XCRD] + 0.5*cell->parameters[CellParams::DX];
      // const Real y  = cell->parameters[CellParams::YCRD] + 0.5*cell->parameters[CellParams::DY];
      // const Real z  = cell->parameters[CellParams::ZCRD] + 0.5*cell->parameters[CellParams::DZ];
 
      const Real mass = getObjectWrapper().particleSpecies[popID].mass;
      Real initRho = sP.DENSITY * (1.0 + sP.densityPertRelAmp * (0.5 - rndRho));
      Real initTx = sP.TEMPERATUREX;
      Real initTy = sP.TEMPERATUREY;
      Real initTz = sP.TEMPERATUREZ;
      const Real initV0X = sP.velocityPertAbsAmp * (0.5 - rndVel[0] );
      const Real initV0Y = sP.velocityPertAbsAmp * (0.5 - rndVel[1] );
      const Real initV0Z = sP.velocityPertAbsAmp * (0.5 - rndVel[2] );
 
      #ifdef USE_GPU
      vmesh::VelocityMesh *vmesh = cell->dev_get_velocity_mesh(popID);
      vmesh::VelocityBlockContainer* VBC = cell->dev_get_velocity_blocks(popID);
      #else
      vmesh::VelocityMesh *vmesh = cell->get_velocity_mesh(popID);
      vmesh::VelocityBlockContainer* VBC = cell->get_velocity_blocks(popID);
      #endif
      // Loop over blocks
      Realf rhosum = 0;
      arch::parallel_reduce<arch::null>(
         {WID, WID, WID, nRequested},
         ARCH_LOOP_LAMBDA (const uint i, const uint j, const uint k, const uint initIndex, Realf *lsum ) {
            vmesh::GlobalID *GIDlist = vmesh->getGrid()->data();
            Realf* bufferData = VBC->getData();
            const vmesh::GlobalID blockGID = GIDlist[initIndex];
            // Calculate parameters for new block
            Real blockCoords[6];
            vmesh->getBlockInfo(blockGID,&blockCoords[0]);
            creal vxBlock = blockCoords[0];
            creal vyBlock = blockCoords[1];
            creal vzBlock = blockCoords[2];
            creal dvxCell = blockCoords[3];
            creal dvyCell = blockCoords[4];
            creal dvzCell = blockCoords[5];
            ARCH_INNER_BODY(i, j, k, initIndex, lsum) {
               creal vx = vxBlock + (i+0.5)*dvxCell - initV0X;
               creal vy = vyBlock + (j+0.5)*dvyCell - initV0Y;
               creal vz = vzBlock + (k+0.5)*dvzCell - initV0Z;
               const Realf value = TriMaxwellianPhaseSpaceDensity(vx,vy,vz,initTx,initTy,initTz,initRho,mass);
               bufferData[initIndex*WID3 + k*WID2 + j*WID + i] = value;
               //lsum[0] += value;
            };
         }, rhosum);
      return rhosum;
   }
 
   /* Evaluates local SpatialCell properties for the project and population,
      then evaluates the phase-space density at the given coordinates.
      Used as a probe for projectTriAxisSearch.
   */
   Realf Fluctuations::probePhaseSpace(spatial_cell::SpatialCell *cell,
                                        const uint popID,
                                        Real vx_in, Real vy_in, Real vz_in
      ) const {
      const FluctuationsSpeciesParameters& sP = speciesParams[popID];
      // Fetch spatial cell center coordinates
      // const Real x  = cell->parameters[CellParams::XCRD] + 0.5*cell->parameters[CellParams::DX];
      // const Real y  = cell->parameters[CellParams::YCRD] + 0.5*cell->parameters[CellParams::DY];
      // const Real z  = cell->parameters[CellParams::ZCRD] + 0.5*cell->parameters[CellParams::DZ];
 
      const Real mass = getObjectWrapper().particleSpecies[popID].mass;
      Real initRho = sP.DENSITY * (1.0 + sP.densityPertRelAmp * (0.5 - rndRho));
      Real initTx = sP.TEMPERATUREX;
      Real initTy = sP.TEMPERATUREY;
      Real initTz = sP.TEMPERATUREZ;
      const Real initV0X = sP.velocityPertAbsAmp * (0.5 - rndVel[0] );
      const Real initV0Y = sP.velocityPertAbsAmp * (0.5 - rndVel[1] );
      const Real initV0Z = sP.velocityPertAbsAmp * (0.5 - rndVel[2] );
      creal vx = vx_in - initV0X;
      creal vy = vy_in - initV0Y;
      creal vz = vz_in - initV0Z;
      const Realf value = TriMaxwellianPhaseSpaceDensity(vx,vy,vz,initTx,initTy,initTz,initRho,mass);
      return value;
   }
 
   void Fluctuations::calcCellParameters(spatial_cell::SpatialCell* cell,creal& t) {
 
      std::default_random_engine rndState;
      setRandomCellSeed(cell,rndState);
 
      this->rndRho=getRandomNumber(rndState);
 
      this->rndVel[0]=getRandomNumber(rndState);
      this->rndVel[1]=getRandomNumber(rndState);
      this->rndVel[2]=getRandomNumber(rndState);
   }
 
   void Fluctuations::setProjectBField(
      fsgrids::perbspan perb,
      fsgrids::bgbspan bgb,
      fsgrids::technicalspan technical, FieldSolverGrid &fsgrid
   ) {
      ConstantField bgField;
      bgField.initialize(this->BX0,
                         this->BY0,
                         this->BZ0);
 
      setBackgroundField(bgField, bgb, technical, fsgrid);
 
      if(!P::isRestart) {
         // local copies for lambda capture
         const auto magXPertAbsAmp_l = this->magXPertAbsAmp;
         const auto magYPertAbsAmp_l = this->magYPertAbsAmp;
         const auto magZPertAbsAmp_l = this->magZPertAbsAmp;
         const auto seed = this->seed;
 
         fsgrid.parallel_for([](int timerId) -> phiprof::Timer { return phiprof::Timer{timerId}; },
                             phiprof::initializeTimer("setProjectBField"), technical,
                             [=](const fsgrid::Coordinates &coordinates, const fsgrid::FsStencil& stencil, cuint sysBoundaryFlag, cuint sysBoundaryLayer) {
            auto& cell = perb[stencil.ooo()];
 
            const auto seedmodifier = coordinates.globalIDFromLocalCoordinates(stencil.i, stencil.j, stencil.k);
            std::default_random_engine rndState_l;
            rndState_l.seed(seed+seedmodifier);
            Real rndBuffer[3];
            rndBuffer[0] = std::uniform_real_distribution<>(-0.5,0.5)(rndState_l);
            rndBuffer[1] = std::uniform_real_distribution<>(-0.5,0.5)(rndState_l);
            rndBuffer[2] = std::uniform_real_distribution<>(-0.5,0.5)(rndState_l);
 
            cell[fsgrids::bfield::PERBX] = magXPertAbsAmp_l * rndBuffer[0];
            cell[fsgrids::bfield::PERBY] = magYPertAbsAmp_l * rndBuffer[1];
            cell[fsgrids::bfield::PERBZ] = magZPertAbsAmp_l * rndBuffer[2];
         });
      }
   }
 
   std::vector<std::array<Real, 3> > Fluctuations::getV0(
      creal x,
      creal y,
      creal z,
      const uint popID
   ) const {
      std::array<Real, 3> V0 {{0.0, 0.0, 0.0}};
      std::vector<std::array<Real, 3> > centerPoints;
      centerPoints.push_back(V0);
      return centerPoints;
   }
   
} // namespace projects