| 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 polynomial.hpp
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| 21 | * @author Julian Iseringhausen <isering@ins.uni-bonn.de>
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| 22 | * @date Mon Nov 21 13:26:56 2011
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| 23 | *
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| 24 | * @brief Class to represent and evaluate a polynomial.
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| 25 | *
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| 26 | */
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| 27 |
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| 28 | #ifndef POLYNOMIAL_HPP_
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| 29 | #define POLYNOMIAL_HPP_
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| 30 |
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| 31 | #include <cstdarg>
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| 32 | #include <vector>
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| 33 |
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| 34 | namespace VMG
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| 35 | {
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| 36 |
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| 37 | class Polynomial
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| 38 | {
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| 39 | public:
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| 40 | Polynomial()
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| 41 | {}
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| 42 |
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| 43 | Polynomial(const int& degree,...) :
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| 44 | coeff(degree+1)
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| 45 | {
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| 46 | va_list vl;
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| 47 | va_start(vl, degree);
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| 48 | for (int i=0; i<=degree; ++i)
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| 49 | coeff[i] = va_arg(vl, vmg_float);
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| 50 | va_end(vl);
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| 51 | }
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| 52 |
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| 53 | Polynomial(const Polynomial& rhs) :
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| 54 | coeff(rhs.coeff.size())
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| 55 | {
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| 56 | for (unsigned int i=0; i<coeff.size(); ++i)
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| 57 | coeff[i] = rhs.coeff[i];
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| 58 | }
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| 59 |
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| 60 | vmg_float operator()(const vmg_float& val) const
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| 61 | {
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| 62 | switch (coeff.size())
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| 63 | {
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| 64 | case 1:
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| 65 | return coeff[0];
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| 66 | case 2:
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| 67 | return coeff[1] * val + coeff[0];
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| 68 | case 3:
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| 69 | return (coeff[2] * val + coeff[1]) * val + coeff[0];
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| 70 | case 4:
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| 71 | return ((coeff[3] * val + coeff[2]) * val + coeff[1]) * val + coeff[0];
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| 72 | case 5:
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| 73 | return (((coeff[4] * val + coeff[3]) * val + coeff[2]) * val + coeff[1]) * val + coeff[0];
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| 74 | case 6:
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| 75 | return ((((coeff[5] * val + coeff[4]) * val + coeff[3]) * val + coeff[2]) * val + coeff[1]) * val + coeff[0];
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| 76 | case 7:
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| 77 | return (((((coeff[6]*val+coeff[5])*val+coeff[4])*val+coeff[3])*val+coeff[2])*val+coeff[1])*val+coeff[0];
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| 78 | case 8:
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| 79 | return ((((((coeff[7]*val+coeff[6])*val+coeff[5])*val+coeff[4])*val+coeff[3])*val+coeff[2])*val+coeff[1])*val+coeff[0];
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| 80 | default:
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| 81 | vmg_float result = coeff.back();
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| 82 | for (int i=coeff.size()-2; i>=0; --i)
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| 83 | result = coeff[i] + result * val;
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| 84 | return result;
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| 85 | }
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| 86 |
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| 87 | }
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| 88 |
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| 89 | Polynomial& operator=(const Polynomial& rhs)
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| 90 | {
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| 91 | coeff.resize(rhs.coeff.size());
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| 92 | for (unsigned int i=0; i<coeff.size(); ++i)
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| 93 | coeff[i] = rhs.coeff[i];
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| 94 |
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| 95 | return *this;
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| 96 | }
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| 97 |
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| 98 | private:
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| 99 | std::vector<vmg_float> coeff;
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| 100 | };
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| 101 |
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| 102 | }
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| 103 |
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| 104 | #endif /* POLYNOMIAL_HPP_ */
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