| 1 | /*
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| 2 | * vmg - a versatile multigrid solver
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| 3 | * Copyright (C) 2012 Institute for Numerical Simulation, University of Bonn
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| 4 | *
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| 5 | * vmg is free software: you can redistribute it and/or modify
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| 6 | * it under the terms of the GNU General Public License as published by
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| 7 | * the Free Software Foundation, either version 3 of the License, or
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| 8 | * (at your option) any later version.
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| 9 | *
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| 10 | * vmg is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 13 | * GNU General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU General Public License
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| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>.
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| 17 | */
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| 18 |
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| 19 | /**
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| 20 | * @file bspline.cpp
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| 21 | * @author Julian Iseringhausen <isering@ins.uni-bonn.de>
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| 22 | * @date Mon Nov 21 13:27:22 2011
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| 23 | *
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| 24 | * @brief B-Splines for molecular dynamics.
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| 25 | *
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| 26 | */
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| 27 |
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| 28 | #ifdef HAVE_CONFIG_H
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| 29 | #include <libvmg_config.h>
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| 30 | #endif
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| 31 |
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| 32 | #ifndef BSPLINE_DEGREE
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| 33 | #error BSPLINE_DEGREE not defined.
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| 34 | #endif
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| 35 |
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| 36 | #if BSPLINE_DEGREE < 3 || BSPLINE_DEGREE > 6
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| 37 | #error Please choose a B-Spline degree between 3 and 6
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| 38 | #endif
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| 39 |
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| 40 | #include "base/helper.hpp"
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| 41 | #include "base/math.hpp"
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| 42 | #include "units/particle/bspline.hpp"
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| 43 |
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| 44 | #define POW(x,y) Helper::pow(x,y)
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| 45 |
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| 46 | using namespace VMG;
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| 47 |
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| 48 | Particle::BSpline::BSpline(const int& near_field_cells, const vmg_float& h) :
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| 49 | spline_nom((BSPLINE_DEGREE+1)/2),
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| 50 | spline_denom((BSPLINE_DEGREE+1)/2),
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| 51 | potential_nom((BSPLINE_DEGREE+1)/2+1),
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| 52 | potential_denom((BSPLINE_DEGREE+1)/2+1),
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| 53 | field_nom((BSPLINE_DEGREE+1)/2),
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| 54 | field_denom((BSPLINE_DEGREE+1)/2),
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| 55 | intervals((BSPLINE_DEGREE+1)/2),
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| 56 | R(near_field_cells*h),
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| 57 | near_field_cells(near_field_cells)
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| 58 | {
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| 59 | for (unsigned int i=0; i<intervals.size(); ++i)
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| 60 | intervals[i] = R * ( -1.0 + 2.0 / static_cast<vmg_float>(BSPLINE_DEGREE) * (i + BSPLINE_DEGREE/2 + 1));
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| 61 |
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| 62 | #if BSPLINE_DEGREE == 3
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| 63 |
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| 64 | spline_nom[0] = Polynomial(2, 81.0*POW(R,2), 0.0, -243.0);
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| 65 | spline_nom[1] = Polynomial(2, 243.0*POW(R,2), -486.0*R, 243.0);
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| 66 |
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| 67 | spline_denom[0] = Polynomial(0, 16.0 * Math::pi * POW(R,5));
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| 68 | spline_denom[1] = Polynomial(0, 32.0 * Math::pi * POW(R,5));
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| 69 |
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| 70 | potential_nom[0] = Polynomial(5,
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| 71 | 0.0,
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| 72 | -195.0*POW(R,4),
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| 73 | 0.0,
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| 74 | 270.0*POW(R,2),
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| 75 | 0.0,
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| 76 | -243.0);
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| 77 |
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| 78 | potential_nom[1] = Polynomial(5,
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| 79 | 2.0 * POW(R,5),
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| 80 | -405.0 * POW(R,4),
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| 81 | 0.0,
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| 82 | 810.0 * POW(R,2),
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| 83 | -810.0 * R,
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| 84 | 243.0);
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| 85 |
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| 86 | potential_nom[2] = Polynomial(0, -1.0);
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| 87 |
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| 88 | potential_denom[0] = Polynomial(0, 80.0*POW(R,5));
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| 89 | potential_denom[1] = Polynomial(0, 160.0*POW(R,5));
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| 90 | potential_denom[2] = Polynomial(0, 1.0);
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| 91 |
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| 92 | field_nom[0] = Polynomial(5,
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| 93 | 20.0 * POW(R,5),
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| 94 | 0.0,
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| 95 | 0.0,
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| 96 | -135.0 * POW(R,2),
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| 97 | 0.0,
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| 98 | 243.0);
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| 99 |
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| 100 | field_nom[1] = Polynomial(5,
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| 101 | 81.0 * POW(R,5),
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| 102 | 0.0,
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| 103 | 0.0,
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| 104 | -810.0 * POW(R,2),
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| 105 | 1215.0 * R,
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| 106 | -486.0);
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| 107 |
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| 108 | field_denom[0] = Polynomial(3,
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| 109 | 0.0,
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| 110 | 0.0,
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| 111 | 0.0,
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| 112 | 20.0 * POW(R,5));
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| 113 |
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| 114 | field_denom[1] = Polynomial(3,
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| 115 | 0.0,
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| 116 | 0.0,
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| 117 | 0.0,
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| 118 | 80.0 * POW(R,5));
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| 119 |
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| 120 | antid = 39.0 / (16.0 * R);
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| 121 |
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| 122 | #elif BSPLINE_DEGREE == 6
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| 123 |
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| 124 | spline_nom[0] = Polynomial(5,
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| 125 | 297.0 * POW(R,5),
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| 126 | 0.0,
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| 127 | -2430.0 * POW(R,3),
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| 128 | 0.0,
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| 129 | 10935.0 * R,
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| 130 | -10935.0);
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| 131 |
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| 132 | spline_nom[1] = Polynomial(5,
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| 133 | 459.0 * POW(R,5),
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| 134 | 2025.0 * POW(R,4),
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| 135 | -17010.0 * POW(R,3),
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| 136 | 36450.0 * POW(R,2),
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| 137 | -32805.0 * R,
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| 138 | 10935.0);
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| 139 |
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| 140 | spline_nom[2] = Polynomial(5,
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| 141 | 2187.0 * POW(R,5),
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| 142 | -10935.0 * POW(R,4),
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| 143 | 21870.0 * POW(R,3),
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| 144 | -21870.0 * POW(R,2),
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| 145 | 10935.0 * R,
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| 146 | -2187.0);
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| 147 |
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| 148 | spline_denom[0] = Polynomial(0, 20.0 * Math::pi * POW(R,8));
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| 149 | spline_denom[1] = Polynomial(0, 40.0 * Math::pi * POW(R,8));
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| 150 | spline_denom[2] = Polynomial(0, 40.0 * Math::pi * POW(R,8));
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| 151 |
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| 152 | potential_nom[0] = Polynomial(8,
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| 153 | 0.0,
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| 154 | -956.0 * POW(R,7),
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| 155 | 0.0,
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| 156 | 2772.0 * POW(R,5),
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| 157 | 0.0,
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| 158 | -6804.0 * POW(R,3),
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| 159 | 0.0,
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| 160 | 14580.0 * R,
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| 161 | -10935.0);
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| 162 |
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| 163 | potential_nom[1] = Polynomial(8,
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| 164 | -5.0 * POW(R,8),
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| 165 | -5676.0 * POW(R,7),
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| 166 | 0.0,
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| 167 | 12852.0 * POW(R,5),
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| 168 | 28350.0 * POW(R,4),
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| 169 | -142884.0 * POW(R,3),
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| 170 | 204120.0 * POW(R,2),
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| 171 | -131220.0 * R,
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| 172 | 32805.0);
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| 173 |
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| 174 | potential_nom[2] = Polynomial(8,
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| 175 | 169.0 * POW(R,8),
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| 176 | -2916.0 * POW(R,7),
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| 177 | 0.0,
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| 178 | 20412.0 * POW(R,5),
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| 179 | -51030.0 * POW(R,4),
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| 180 | 61236.0 * POW(R,3),
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| 181 | -40824.0 * POW(R,2),
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| 182 | 14580.0 * R,
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| 183 | -2187.0);
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| 184 |
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| 185 | potential_nom[3] = Polynomial(0, -1.0);
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| 186 |
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| 187 | potential_denom[0] = Polynomial(0, 280.0 * POW(R,8));
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| 188 | potential_denom[1] = Polynomial(0, 1680.0 * POW(R,8));
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| 189 | potential_denom[2] = Polynomial(0, 560.0 * POW(R,8));
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| 190 | potential_denom[3] = Polynomial(0, 0.0);
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| 191 |
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| 192 | field_nom[0] = Polynomial(8,
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| 193 | 280.0 * POW(R,8),
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| 194 | 0.0,
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| 195 | 0.0,
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| 196 | -5544.0 * POW(R,5),
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| 197 | 0.0,
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| 198 | 27216.0 * POW(R,3),
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| 199 | 0.0,
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| 200 | -87480.0 * R,
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| 201 | 76545.0);
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| 202 |
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| 203 | field_nom[1] = Polynomial(8,
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| 204 | 1675.0 * POW(R,8),
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| 205 | 0.0,
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| 206 | 0.0,
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| 207 | -25704.0 * POW(R,5),
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| 208 | -85050.0 * POW(R,4),
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| 209 | 571536.0 * POW(R,3),
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| 210 | -1020600.0 * POW(R,2),
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| 211 | 787320.0 * R,
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| 212 | -229635.0);
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| 213 |
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| 214 | field_nom[2] = Polynomial(8,
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| 215 | 729.0 * POW(R,8),
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| 216 | 0.0,
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| 217 | 0.0,
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| 218 | -40824.0 * POW(R,5),
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| 219 | 153090.0 * POW(R,4),
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| 220 | -244944.0 * POW(R,3),
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| 221 | 204120.0 * POW(R,2),
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| 222 | -87480.0 * R,
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| 223 | 15309.0);
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| 224 |
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| 225 | field_denom[0] = Polynomial(3,
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| 226 | 0.0,
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| 227 | 0.0,
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| 228 | 0.0,
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| 229 | 280.0 * POW(R,8));
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| 230 | field_denom[1] = Polynomial(3,
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| 231 | 0.0,
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| 232 | 0.0,
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| 233 | 0.0,
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| 234 | 1680.0 * POW(R,8));
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| 235 |
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| 236 | field_denom[2] = Polynomial(3,
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| 237 | 0.0,
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| 238 | 0.0,
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| 239 | 0.0,
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| 240 | 560.0 * POW(R,8));
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| 241 |
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| 242 | antid = 239.0 / (70.0 * R);
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| 243 |
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| 244 | #else
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| 245 | #error B-Spline degree not supported. Choose 3 or 6.
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| 246 | #endif /* BSPLINE_DEGREE */
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| 247 | }
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