135 lines
4.2 KiB
C++
135 lines
4.2 KiB
C++
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/*
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* Copyright (c) 2015 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: David Guillen Fandos
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*/
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#ifndef __SIM_LINEAR_SOLVER_HH__
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#define __SIM_LINEAR_SOLVER_HH__
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#include <cassert>
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#include <sstream>
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#include <string>
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#include <vector>
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/**
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* This class describes a linear equation with constant coefficients.
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* The equation has a certain (variable) number of unkowns and it can hold
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* N+1 coefficients.
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*/
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class LinearEquation {
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public:
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LinearEquation(unsigned unknowns) {
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eq = std::vector <double> (unknowns + 1, 0);
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}
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// Add two equations
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LinearEquation operator+ (const LinearEquation& rhs) {
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assert(this->eq.size() == rhs.eq.size());
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LinearEquation res(this->eq.size() - 1);
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for (unsigned i = 0; i < res.eq.size(); i++)
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res.eq[i] = this->eq[i] + rhs.eq[i];
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return res;
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}
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// Multiply the equation by a constant
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LinearEquation & operator*= (const double cnt) {
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for (auto & c: eq)
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c *= cnt;
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return *this;
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}
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// Access a certain equation coefficient
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double & operator[] (unsigned unkw) {
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assert(unkw < eq.size());
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return eq[unkw];
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}
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// Get a string representation
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std::string toStr() const {
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std::ostringstream oss;
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for (unsigned i = 0; i < eq.size(); i++) {
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if (i)
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oss << " + ";
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oss << eq[i];
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if (i != eq.size() - 1)
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oss << "*x" << i;
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}
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oss << " = 0";
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return oss.str();
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}
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// Index for the constant term
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unsigned cnt() const { return eq.size() - 1; }
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private:
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/** Coefficients */
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std::vector <double> eq;
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};
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class LinearSystem {
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public:
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LinearSystem(unsigned unknowns) {
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for (unsigned i = 0; i < unknowns; i++)
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matrix.push_back(LinearEquation(unknowns));
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}
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LinearEquation & operator[] (unsigned eq) {
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assert(eq < matrix.size());
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return matrix[eq];
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}
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std::string toStr() const {
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std::string r;
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for (auto & eq: matrix)
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r += eq.toStr() + "\n";
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return r;
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}
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std::vector <double> solve() const;
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private:
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std::vector < LinearEquation > matrix;
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};
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#endif
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