72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
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#pragma once
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#ifndef utils_h
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#define utils_h
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#include "LevenbergMarquardt.h"
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#include <Eigen/Dense>
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#include <cmath>
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#include <iostream>
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double Gaussian(double x, double* p) {
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return p[0] * exp(-(x - p[1]) * (x - p[1]) / (2 * p[2] * p[2]));
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}
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double* GaussianJacobian(double x, double* p) {
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double* resJ = new double[3];
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resJ[0] = -Gaussian(x, p) / p[0];
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resJ[1] = -(x - p[1]) * Gaussian(x, p) / (p[2] * p[2]);
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resJ[2] = -(x - p[1]) * (x - p[1]) * Gaussian(x, p) / (p[2] * p[2] * p[2]);
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return resJ;
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}
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class GaussFit {
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public:
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GaussFit();
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~GaussFit();
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public:
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void addData(double x, double y);
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double* fit();
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public:
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double* parma = new double[3];
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std::vector<Eigen::Vector2d> data;
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};
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GaussFit::GaussFit() {}
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GaussFit::~GaussFit() {}
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void GaussFit::addData(double x, double y) { data.push_back(Eigen::Vector2d(x, y)); }
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double* GaussFit::fit() {
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int n = data.size();
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double x, y, sigma;
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Eigen::VectorXd mY(n);
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Eigen::MatrixXd mX(n, 3);
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Eigen::MatrixXd mB(3, 1);
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for (int i = 0; i < n; i++) {
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Eigen::Vector2d& point = data.at(i);
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x = point(0), y = point(1);
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mY(i, 0) = log(y);
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mX(i, 0) = 1, mX(i, 1) = x, mX(i, 2) = x * x;
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}
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mB = (mX.transpose() * mX).inverse() * mX.transpose() * mY;
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sigma = -1 / mB(2, 0);
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parma[1] = mB(1, 0) * sigma / 2;
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parma[0] = exp(mB(0, 0) + parma[1] * parma[1] / sigma);
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parma[2] = sqrt(sigma);
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LevenbergMarquardt LM(3, parma, Gaussian, GaussianJacobian);
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LM.data = data;
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parma = LM.solve();
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return parma;
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}
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#endif
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