SectorMagneticFieldMap.cpp

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/*
 *  Copyright (c) 2012, Chris Rogers
 *  All rights reserved.
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *  3. Neither the name of STFC nor the names of its contributors may be used to
 *     endorse or promote products derived from this software without specific
 *     prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */
 
 
#include "Fields/SectorMagneticFieldMap.h"
// Grid on which field values are stored
#include "Fields/Interpolation/Mesh.h"
#include "Fields/Interpolation/ThreeDGrid.h"
// Linear interpolation routines
#include "Fields/Interpolation/VectorMap.h"
#include "Fields/Interpolation/Interpolator3dGridTo3d.h"
// Higher order interpolation routines
#include "Fields/Interpolation/PolynomialPatch.h"
#include "Fields/Interpolation/PPSolveFactory.h"
 
#include "Utilities/LogicalError.h"
 
#include <algorithm>
#include <cmath>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
 
using namespace interpolation;
 
extern Inform *gmsg;
 
// allow a fairly generous phi tolerance - we don't care about phi much and
// calculation can be flaky due to ascii truncation of double and conversions
// from polar to Cartesian
const double SectorMagneticFieldMap::fractionalBBPhiTolerance_m(1e-12);
std::map<std::string, SectorMagneticFieldMap*> SectorMagneticFieldMap::_fields;
 
SectorMagneticFieldMap::SectorMagneticFieldMap(std::string file_name,
                                               std::string symmetry,
                                               double length_units,
                                               double field_units,
                                               int polynomial_order,
                                               int smoothing_order)
       : SectorField(file_name), interpolator_m(nullptr), symmetry_m(dipole),
         units_m(6, 1.), filename_m(file_name), phiOffset_m(0.),
         poly_order_m(polynomial_order), smoothing_order_m(smoothing_order) {
    units_m[0] *= length_units;
    units_m[1] *= length_units;
    units_m[2] *= length_units;
    units_m[3] *= field_units;
    units_m[4] *= field_units;
    units_m[5] *= field_units;
    setSymmetry(symmetry);
    if (_fields.find(file_name) == _fields.end()) {
        readMap();
        _fields[file_name] = new SectorMagneticFieldMap(*this);
    } else {
        SectorMagneticFieldMap* tgt = _fields[file_name];
        if (symmetry_m != tgt->symmetry_m ||
            units_m != tgt->units_m ||
            filename_m != tgt->filename_m) {
            throw(LogicalError(
                    "SectorMagneticFieldMap::SectorMagneticFieldMap",
                    "Attempt to construct different SectorFieldMaps with same "+
                    std::string("file but different settings")
                  ));
        }
        setInterpolator(tgt->interpolator_m);
    }
    ThreeDGrid* grid = dynamic_cast<ThreeDGrid*>(interpolator_m->getMesh());
    phiOffset_m = -grid->minZ();
}
 
SectorMagneticFieldMap::SectorMagneticFieldMap
                                           (const SectorMagneticFieldMap& field)
    : SectorField(field), interpolator_m(nullptr), symmetry_m(field.symmetry_m),
      units_m(field.units_m),
      filename_m(field.filename_m), phiOffset_m(field.phiOffset_m) {
    VectorMap* interpolator = nullptr;
    if (field.interpolator_m != nullptr) {
        interpolator = field.interpolator_m;
    }
    setInterpolator(interpolator);
}
 
SectorMagneticFieldMap::~SectorMagneticFieldMap() {
    // delete interpolator_m; We reuse the interpolators... hack! should use smart pointer
}
 
VectorMap* SectorMagneticFieldMap::getInterpolator() {
    return interpolator_m;
}
 
void SectorMagneticFieldMap::setInterpolator(VectorMap* interpolator) {
    if (interpolator_m != nullptr) {
        delete interpolator_m;
    }
    interpolator_m = interpolator;
    if (interpolator_m != nullptr) {
        if (interpolator_m->getPointDimension() != 3)
            throw(LogicalError(
                      "SectorMagneticFieldMap::setInterpolator",
                      "Attempt to load interpolator with PointDimension != 3")
                  );
        if (interpolator_m->getValueDimension() != 3)
            throw(LogicalError(
                      "SectorMagneticFieldMap::setInterpolator",
                      "Attempt to load interpolator with ValueDimension != 3"
                  ));
        ThreeDGrid* grid = dynamic_cast<ThreeDGrid*>(interpolator_m->getMesh());
        if (grid == nullptr)
            throw(LogicalError(
                      "SectorMagneticFieldMap::setInterpolator",
                      "Attempt to load interpolator with grid not ThreeDGrid"
                  ));
        SectorField::setPolarBoundingBox
                                    (grid->minX(), grid->minY()-grid->maxY(), grid->minZ(),
                                     grid->maxX(), grid->maxY(), grid->maxZ(),
                                     0., 0., 0.);
    }
    getInfo(gmsg);
}
 
std::string SectorMagneticFieldMap::getSymmetry() const {
    return SymmetryToString(symmetry_m);
}
 
void SectorMagneticFieldMap::setSymmetry(std::string name) {
    symmetry_m = StringToSymmetry(name);
}
 
void SectorMagneticFieldMap::readMap() {
    VectorMap* interpolator = IO::readMap
             (filename_m, units_m, symmetry_m, poly_order_m, smoothing_order_m);
    setInterpolator(interpolator);
 
}
 
void SectorMagneticFieldMap::freeMap() {
    setInterpolator(nullptr);
}
 
SectorMagneticFieldMap::symmetry SectorMagneticFieldMap::StringToSymmetry
                                                             (std::string sym) {
    if (sym == "None") {
        return none;
    }
    if (sym == "Dipole") {
        return dipole;
    }
    throw(LogicalError(
            "SectorMagneticFieldMap::StringToSymmetry",
            "Didn't recognise symmetry type "+sym
          ));
}
 
std::string SectorMagneticFieldMap::SymmetryToString
                                        (SectorMagneticFieldMap::symmetry sym) {
    if (sym == none) {
        return "None";
    }
    if (sym == dipole) {
        return "Dipole";
    }
    throw(LogicalError(
            "SectorMagneticFieldMap::SymmetryToString",
            "Didn't recognise symmetry type " + std::to_string(sym)
          ));
}
 
/*
bool SectorMagneticFieldMap::getFieldstrengthPolar
                    (const Vector_t<double, 3> &R_p, Vector_t<double, 3> &, Vector_t<double, 3> &B_p) const {
    // vector_t::operator[i] const returns by value, not by const reference
    // so we need to make an array here
    double R_temp[3] = {R_p[0], R_p[1], R_p[2]};
    R_temp[2] += phiOffset_m;
    // bounding box
    if (!isInBoundingBox(R_temp))
        return true;
    interpolator_m->function(R_temp, &B_p[0]);
    SectorField::convertToPolar(R_temp, &(B_p[0]));
    return false;
}
*/
 
bool SectorMagneticFieldMap::getFieldstrength (
        const Vector_t<double, 3> &R_c, Vector_t<double, 3> &/*E_c*/, Vector_t<double, 3> &B_c) const {
    // coordinate transform; field is in the x-z plane but OPAL-CYCL assumes
    // x-y plane; rotate to the start of the bend and into polar coordinates;
    // apply mirror symmetry about the midplane
    double radius   = (getPolarBoundingBoxMin()[0]+getPolarBoundingBoxMax()[0])/2;
    double midplane = (getPolarBoundingBoxMin()[1]+getPolarBoundingBoxMax()[1])/2;
    double R_temp[3] = {R_c(0)+radius, R_c(1), R_c(2)};
    double B_temp[3] = {0., 0., 0.};
    SectorField::convertToPolar(R_temp);
    bool mirror = R_temp[1] < midplane;
    if (mirror) {
        R_temp[1] = midplane + (midplane - R_temp[1]);
    }
    // interpolator has phi in 0. to dphi
    R_temp[2] -= phiOffset_m;
    // bool symmetryWasApplied = applySymmetry(R_temp);
    if (!isInBoundingBox(R_temp)) {
        return true;
    }
    interpolator_m->function(R_temp, B_temp);
    // and here we transform back
    // we want phi in 0. to dphi
    if (mirror) {
        B_temp[0] *= -1; // reflect Bx
        B_temp[2] *= -1; // reflect Bz
    }
    B_c(0) = B_temp[0]*cos(phiOffset_m)-B_temp[2]*sin(phiOffset_m); // x
    B_c(1) = B_temp[1]; // axial
    B_c(2) = B_temp[0]*sin(phiOffset_m)+B_temp[2]*cos(phiOffset_m); // z
    return false;
}
 
bool SectorMagneticFieldMap::applySymmetry(double* R_temp) const {
    double ymin = SectorField::getPolarBoundingBoxMin()[1];
    if (symmetry_m == dipole && R_temp[1] <= ymin) {
        R_temp[1] = 2*ymin-R_temp[1];
        return true;
    }
    return false;
}
 
void SectorMagneticFieldMap::clearFieldCache() {
    for (std::map<std::string, SectorMagneticFieldMap*>::iterator it =
                                   _fields.begin(); it != _fields.end(); ++it) {
        delete (*it).second;
    }
    _fields = std::map<std::string, SectorMagneticFieldMap*>();
}
 
void SectorMagneticFieldMap::getInfo(Inform* msg) {
   std::vector<double> bbmin = SectorField::getPolarBoundingBoxMin();
   std::vector<double> bbmax = SectorField::getPolarBoundingBoxMax();
   (*msg) << Filename_m << " (3D Sector Magnetostatic);\n"
          << "  zini=   " << bbmin[1] << " mm;  zfinal= " << bbmax[1] << " mm;\n"
          << "  phiini= " << bbmin[2] << " rad; phifinal= " << bbmax[2] << " rad;\n"
          << "  rini=   " << bbmin[0] << " mm;  rfinal=  " << bbmax[0] << " mm;"
          << endl;
}
 
void SectorMagneticFieldMap::print(std::ostream& out) {
   std::vector<double> bbmin = SectorField::getPolarBoundingBoxMin();
   std::vector<double> bbmax = SectorField::getPolarBoundingBoxMax();
   out << Filename_m << " (3D Sector Magnetostatic);\n"
       << "  zini= " << bbmin[1] << " m; zfinal= " << bbmax[1] << " mm;\n"
       << "  phiini= " << bbmin[2] << " rad; phifinal= " << bbmax[2] << " rad;\n"
       << "  rini= " << bbmin[0] << " m; rfinal= " << bbmax[0] << " mm;\n"
       << std::endl;
}
 
bool SectorMagneticFieldMap::getFieldDerivative(const Vector_t<double, 3> &/*R*/, Vector_t<double, 3> &/*E*/,
                                                Vector_t<double, 3> &/*B*/, const DiffDirection &/*dir*/) const {
    throw(LogicalError("SectorMagneticFieldMap::getFieldDerivative",
                       "Field map derivatives not implemented"));
}
 
void SectorMagneticFieldMap::swap() {}
 
 
double SectorMagneticFieldMap::getDeltaPhi() const {
    ThreeDGrid* grid = reinterpret_cast<ThreeDGrid*>(interpolator_m->getMesh());
    return grid->maxZ() - grid->minZ();
}
 
const double SectorMagneticFieldMap::IO::floatTolerance_m = 1e-3;
const int SectorMagneticFieldMap::IO::sortOrder_m[3] = {0, 1, 2};
 
VectorMap* SectorMagneticFieldMap::IO::readMap(
                          std::string file_name,
                          std::vector<double> units,
                          SectorMagneticFieldMap::symmetry sym,
                          int polynomial_order,
                          int smoothing_order) {
    try {
        *gmsg <<"* Opening sector field map " << file_name
                << " fit order " << polynomial_order
                << " smoothing order " << smoothing_order << endl;
        // get raw data
        std::vector< std::vector<double> > field_points = readLines
                                                             (file_name, units);
        // build grid
        ThreeDGrid* grid = generateGrid(field_points, sym);
        // build interpolator (convert grid to useful units)
        if (polynomial_order == 1 && smoothing_order == 1) {
            VectorMap* interpolator = getInterpolator(field_points, grid, sym);
            return interpolator;
        } else {
            VectorMap* interpolator = getInterpolatorPolyPatch(
                                  field_points,
                                  grid,
                                  sym,
                                  polynomial_order,
                                  smoothing_order);
            return interpolator;
        }
    } catch(std::exception& exc) {
        throw(LogicalError(
                     "SectorMagneticFieldMap::IO::ReadMap",
                     "Failed to read file "+file_name+" with "+(&exc)->what()
               ));
    }
    return nullptr;
}
 
VectorMap* SectorMagneticFieldMap::IO::getInterpolatorPolyPatch(
                          std::vector< std::vector<double> > field_points,
                          ThreeDGrid* grid,
                          SectorMagneticFieldMap::symmetry sym,
                          int polynomial_order,
                          int smoothing_order) {
    // too lazy to write code to handle this case - not available to user anyway
    if (sym != SectorMagneticFieldMap::dipole) {
        throw(LogicalError(
                     "SectorMagneticFieldMap::IO::getInterpolatorPolyPatch",
                     "Failed to recognise symmetry type"
               ));
    }
    std::vector< std::vector<double> > data(field_points.size(),
                                            std::vector<double>(3));
    for (size_t i = 0; i < field_points.size(); ++i) {
        data[i][0] = field_points[i][3];
        data[i][1] = field_points[i][4];
        data[i][2] = field_points[i][5];
    }
    // symmetry is dipole
    try {
        *gmsg << "Calculating polynomials..." << endl;
        PPSolveFactory solver(grid, data, polynomial_order, smoothing_order);
        PolynomialPatch* patch = solver.solve();
        *gmsg << "                       ... done" << endl;
        return patch;
    } catch (GeneralClassicException& exc) {
        throw;
    }
 
}
 
const std::string SectorMagneticFieldMap::IO::errMsg1 =
    std::string("field points during read ")+
    std::string("operation; this could mean that the field ")+
    std::string("map was not complete, or that OPAL could ")+
    std::string("not calculate regular grid spacings properly. ")+
    std::string("Check that the field map is on a cylindrical ")+
    std::string("grid written in Cartesian coordinates and the ")+
    std::string("grid points are written with enough precision (")+
    std::string("check the grid size information above).");
 
VectorMap* SectorMagneticFieldMap::IO::getInterpolator
                        (const std::vector< std::vector<double> > field_points,
                         ThreeDGrid* grid,
                         SectorMagneticFieldMap::symmetry /*sym*/) {
    // build field arrays
    double *** Bx, *** By, *** Bz;
    int index = 0;
    Bx = new double**[grid->xSize()];
    By = new double**[grid->xSize()];
    Bz = new double**[grid->xSize()];
    for (int i = 0; i < grid->xSize(); ++i) {
        Bx[i] = new double*[grid->ySize()];
        By[i] = new double*[grid->ySize()];
        Bz[i] = new double*[grid->ySize()];
        for (int j = 0; j < grid->ySize(); ++j) {
            Bx[i][j] = new double[grid->zSize()];
            By[i][j] = new double[grid->zSize()];
            Bz[i][j] = new double[grid->zSize()];
            for (int k = 0; k < grid->zSize(); ++k) {
                if (index >= int(field_points.size())) {
                    throw(
                        LogicalError(
                          "SectorMagneticFieldMap::IO::getInterpolator",
                          "Ran out of "+errMsg1)
                    );
                }
                Bx[i][j][k] = field_points[index][3];
                By[i][j][k] = field_points[index][4];
                Bz[i][j][k] = field_points[index][5];
                ++index;
            }
        }
    }
    if (index != int(field_points.size())) {
        throw(LogicalError(
                     "SectorMagneticFieldMap::IO::getInterpolator",
                     "Too many "+errMsg1
               ));
    }
    Interpolator3dGridTo3d* interpolator = new Interpolator3dGridTo3d(grid, Bx, By, Bz);
    VectorMap* interpolatorMap = dynamic_cast<VectorMap*>(interpolator);
    return interpolatorMap;
}
 
bool SectorMagneticFieldMap::IO::comparator(std::vector<double> field_item1,
                     std::vector<double> field_item2) {
    const int* order = sortOrder_m;
    if (std::abs(field_item1[order[0]] - field_item2[order[0]]) > floatTolerance_m) {
        return field_item1[order[0]] < field_item2[order[0]];
    }
    if (std::abs(field_item1[order[1]] - field_item2[order[1]]) > floatTolerance_m) {
        return field_item1[order[1]] < field_item2[order[1]];
    }
    return field_item1[order[2]] < field_item2[order[2]];
}
 
std::vector< std::vector<double> > SectorMagneticFieldMap::IO::readLines
                             (std::string file_name, std::vector<double> units) {
    std::vector< std::vector<double> > field_points;
    std::string line;
    if (units.size() != 6) {
        throw(LogicalError(
                     "SectorMagneticFieldMap::IO::ReadLines",
                     "Units should be of length 6"
               ));
    }
 
    std::ifstream fin(file_name.c_str());
    if (!fin || !fin.is_open()) {
        throw(LogicalError(
                     "SectorMagneticFieldMap::IO::ReadLines",
                     "Failed to open file "+file_name
               ));
    }
    // skip header lines
    *gmsg << "* Opened "+file_name << endl;
    for (size_t i = 0; i < 8; ++i) {
        std::getline(fin, line);
    }
    // read in field map
    int line_number = 0;
    while (fin) {
        std::vector<double> field(6);
        fin >> field[0] >> field[1] >> field[2] >> field[3] >> field[4]
            >> field[5];
        if (fin) {
            for (size_t i = 0; i < 6; ++i) {
                field[i] *= units[i];
            }
            field_points.push_back(field);
            line_number++;
        }
    }
    *gmsg << "* Read " << line_number << " lines" << endl;
 
    // convert coordinates to polar; nb we leave field as cartesian
    for (size_t i = 0; i < field_points.size(); ++i) {
        SectorField::convertToPolar(&field_points[i][0]);
    }
 
    // force check sort order
    std::sort(field_points.begin(), field_points.end(),
                                        SectorMagneticFieldMap::IO::comparator);
    return field_points;
}
 
bool SectorMagneticFieldMap::IO::floatGreaterEqual(double in1, double in2) {
    in2 = in2*(1+floatTolerance_m)+floatTolerance_m;
    return in1 > in2;
}
 
ThreeDGrid* SectorMagneticFieldMap::IO::generateGrid
                       (const std::vector< std::vector<double> > field_points,
                        SectorMagneticFieldMap::symmetry /*sym*/) {
    std::vector<double>   r_grid(1, field_points[0][0]);
    std::vector<double>   y_grid(1, field_points[0][1]);
    std::vector<double> phi_grid(1, field_points[0][2]);
    for (size_t i = 0; i < field_points.size(); ++i) {
        if (floatGreaterEqual(field_points[i][0], r_grid.back())) {
            r_grid.push_back(field_points[i][0]);
        }
        if (floatGreaterEqual(field_points[i][1], y_grid.back())) {
            y_grid.push_back(field_points[i][1]);
        }
        if (floatGreaterEqual(field_points[i][2], phi_grid.back())) {
            phi_grid.push_back(field_points[i][2]);
        }
    }
    
    // reflect about y if symmetry is dipole
    *gmsg << "* Grid size (r, y, phi) = ("
          << r_grid.size() << ", " << y_grid.size() << ", " << phi_grid.size()
          << ")" << endl;
    *gmsg << "* Grid min (r [mm], y [mm], phi [rad]) = ("
          << r_grid[0] << ", " << y_grid[0] << ", " << phi_grid[0]
          << ")" << endl;
    *gmsg << "* Grid max (r [mm], y [mm], phi [rad]) = ("
          << r_grid.back() << ", " << y_grid.back() << ", " << phi_grid.back()
          << ")" << endl;
 
    ThreeDGrid* grid = new ThreeDGrid(r_grid, y_grid, phi_grid);
    grid->setConstantSpacing(true);
    return grid;
}