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2021-10-14 13:47:35 +02:00
#include "geometry/Metrics.hpp"
#include "geometry/Basics.hpp"
#include "geometry/Geodesic.hpp"
#include "geometry/Distance.hpp"
#include "geometry/Mean.hpp"
#include <unsupported/Eigen/MatrixFunctions>
#include <iostream>
namespace Geometry {
//static const double EPSILON = 0.000000001; // 10^{-9}
static const double EPSILON = 0.0001; // 10^{-4}
static const size_t ITER_MAX = 50;
//---------------------------------------------------------------------------------------------------
bool Mean(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean, const EMetric metric)
{
if (covs.empty()) { return false; } // If no matrix in vector
if (covs.size() == 1) // If just one matrix in vector
{
mean = covs[0];
return true;
}
if (!HaveSameSize(covs))
{
std::cout << "Matrices haven't same size." << std::endl;
return false;
}
// Force Square Matrix for non Euclidian and non Identity metric
if (!IsSquare(covs[0]) && (metric != EMetric::Euclidian && metric != EMetric::Identity))
{
std::cout << "Non Square Matrix is invalid with " << toString(metric) << " metric." << std::endl;
return false;
}
switch (metric) // Switch method
{
case EMetric::Riemann: return MeanRiemann(covs, mean);
case EMetric::Euclidian: return MeanEuclidian(covs, mean);
case EMetric::LogEuclidian: return MeanLogEuclidian(covs, mean);
case EMetric::LogDet: return MeanLogDet(covs, mean);
case EMetric::Kullback: return MeanKullback(covs, mean);
case EMetric::ALE: return MeanALE(covs, mean);
case EMetric::Harmonic: return MeanHarmonic(covs, mean);
case EMetric::Wasserstein: return MeanWasserstein(covs, mean);
case EMetric::Identity:
default: return MeanIdentity(covs, mean);
}
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool AJDPham(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& ajd, double /*epsilon*/, const int /*maxIter*/)
{
MeanIdentity(covs, ajd);
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanRiemann(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
size_t i = 0; // Index of Covariance Matrix => i
double nu = 1.0, // Coefficient change => nu
tau = std::numeric_limits<double>::max(), // Coefficient change criterion => tau
crit = std::numeric_limits<double>::max(); // Current change => crit
if (!MeanEuclidian(covs, mean)) { return false; } // Initial Mean
while (i < ITER_MAX && EPSILON < crit && EPSILON < nu) // Stopping criterion
{
i++; // Iteration Criterion
const Eigen::MatrixXd sC = mean.sqrt(), isC = sC.inverse(); // Square root & Inverse Square root of Mean => sC & isC
Eigen::MatrixXd mJ = Eigen::MatrixXd::Zero(n, n); // Change => J
for (const auto& cov : covs) { mJ += (isC * cov * isC).log(); } // Sum of log(isC*Ci*isC)
mJ /= double(k); // Normalization
crit = mJ.norm(); // Current change criterion
mean = sC * (nu * mJ).exp() * sC; // Update Mean => M = sC * exp(nu*J) * sC
const double h = nu * crit; // Update Coefficient change
if (h < tau)
{
nu *= 0.95;
tau = h;
}
else { nu *= 0.5; }
}
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanEuclidian(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
mean = Eigen::MatrixXd::Zero(n, n); // Initial Mean
for (const auto& cov : covs) { mean += cov; } // Sum of Ci
mean /= double(k); // Normalization
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanLogEuclidian(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
mean = Eigen::MatrixXd::Zero(n, n); // Initial Mean
for (const auto& cov : covs) { mean += cov.log(); } // Sum of log(Ci)
mean = (mean / double(k)).exp(); // Normalization
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanLogDet(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
size_t i = 0; // Index of Covariance Matrix => i
double crit = std::numeric_limits<double>::max(); // Current change => crit
if (!MeanEuclidian(covs, mean)) { return false; } // Initial Mean
while (i < ITER_MAX && EPSILON < crit) // Stopping criterion
{
i++; // Iteration Criterion
Eigen::MatrixXd mJ = Eigen::MatrixXd::Zero(n, n); // Change => J
for (const auto& cov : covs) { mJ += (0.5 * (cov + mean)).inverse(); } // Sum of ((Ci+M)/2)^{-1}
mJ = (mJ / double(k)).inverse(); // Normalization
crit = (mJ - mean).norm(); // Current change criterion
mean = mJ; // Update mean
}
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanKullback(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
Eigen::MatrixXd m1, m2;
if (!MeanEuclidian(covs, m1)) { return false; }
if (!MeanHarmonic(covs, m2)) { return false; }
if (!GeodesicRiemann(m1, m2, mean, 0.5)) { return false; }
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanWasserstein(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
size_t i = 0; // Index of Covariance Matrix => i
double crit = std::numeric_limits<double>::max(); // Current change => crit
if (!MeanEuclidian(covs, mean)) { return false; } // Initial Mean
Eigen::MatrixXd sC = mean.sqrt(); // Square root of Mean => sC
while (i < ITER_MAX && EPSILON < crit) // Stopping criterion
{
i++; // Iteration Criterion
Eigen::MatrixXd mJ = Eigen::MatrixXd::Zero(n, n); // Change => J
for (const auto& cov : covs) { mJ += (sC * cov * sC).sqrt(); } // Sum of sqrt(sC*Ci*sC)
mJ /= double(k); // Normalization
const Eigen::MatrixXd sJ = mJ.sqrt(); // Square root of change => sJ
crit = (sJ - sC).norm(); // Current change criterion
sC = sJ; // Update sC
}
mean = sC * sC; // Un-square root
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanALE(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
size_t i = 0; // Index of Covariance Matrix => i
double crit = std::numeric_limits<double>::max(); // Change criterion => crit
if (!AJDPham(covs, mean)) { return false; } // Initial Mean
Eigen::MatrixXd mJ; // Change
while (i < ITER_MAX && EPSILON < crit) // Stopping criterion
{
i++; // Iteration Criterion
mJ = Eigen::MatrixXd::Zero(n, n); // Change => J
for (const auto& cov : covs) { mJ += (mean.transpose() * cov * mean).log(); } // Sum of log(C^T*Ci*C)
mJ /= double(k); // Normalization
Eigen::MatrixXd update = mJ.exp().diagonal().asDiagonal(); // Update Form => U
mean = mean * update.sqrt().inverse(); // Update Mean M = M * U^{-1/2}
crit = DistanceRiemann(Eigen::MatrixXd::Identity(n, n), update);
}
mJ = Eigen::MatrixXd::Zero(n, n); // Last Change => J
for (const auto& cov : covs) { mJ += (mean.transpose() * cov * mean).log(); } // Sum of log(C^T*Ci*C)
mJ /= double(k); // Normalization
Eigen::MatrixXd mA = mean.inverse();
mean = mA.transpose() * mJ.exp() * mA;
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanHarmonic(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
const size_t k = covs.size(), n = covs[0].rows(); // Number of Matrix & Features => K & N
mean = Eigen::MatrixXd::Zero(n, n); // Initial Mean
for (const auto& cov : covs) { mean += cov.inverse(); } // Sum of Inverse
mean = (mean / double(k)).inverse(); // Normalization and inverse
return true;
}
//---------------------------------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------------
bool MeanIdentity(const std::vector<Eigen::MatrixXd>& covs, Eigen::MatrixXd& mean)
{
mean = Eigen::MatrixXd::Identity(covs[0].rows(), covs[0].cols());
return true;
}
//---------------------------------------------------------------------------------------------------
} // namespace Geometry