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Add construct and destroy methods to custom_allocator
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nhance custom allocator for Boost compatibility and improve numerical stability in polyfit function
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devin-ai-integration[bot] authored and ohhmm committed Oct 18, 2024
1 parent bd8e396 commit 3f738a1
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64 changes: 36 additions & 28 deletions omnn/extrapolator/Extrapolator.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -7,33 +7,43 @@
#include "math/Integer.h"
#include "math/Sum.h"

#include <boost/numeric/ublas/storage.hpp>


using namespace omnn;
using namespace math;
using namespace boost::numeric::ublas;


auto det_fast(extrapolator_base_matrix matrix)
{
using T = extrapolator_base_matrix::value_type;
ublas::permutation_matrix<std::size_t> pivots(matrix.size1());
// Ensure that matrix_t, vector_t, and permutation_matrix_t are using unbounded_array_wrapper with custom_allocator
using matrix_t = boost::numeric::ublas::matrix<Valuable, boost::numeric::ublas::basic_row_major<>, unbounded_array_wrapper<Valuable, custom_allocator<Valuable>>>;
using vector_t = boost::numeric::ublas::vector<Valuable, unbounded_array_wrapper<Valuable, custom_allocator<Valuable>>>;
using permutation_matrix_t = boost::numeric::ublas::permutation_matrix<std::size_t, unbounded_array_wrapper<std::size_t, custom_allocator<std::size_t>>>;

// This function calculates the determinant of a matrix using LU factorization
auto det_fast(matrix_t matrix) {
// Use the matrix's size1 directly to avoid calling size on the allocator
auto matrix_size = matrix.size1();
permutation_matrix_t pivots(matrix_size);

auto isSingular = ublas::lu_factorize(matrix, pivots);
// Perform LU factorization on a copy of the matrix to preserve the original matrix
matrix_t matrix_copy(matrix);
auto isSingular = ublas::lu_factorize(matrix_copy, pivots);
if (isSingular)
return T(0);
return Valuable(0);

T det = 1;
for (std::size_t i = 0; i < pivots.size(); ++i)
{
Valuable det(1);
for (std::size_t i = 0; i < matrix_size; ++i) {
if (pivots(i) != i)
det *= static_cast<double>(-1);
det *= Valuable(-1);

det *= matrix(i, i);
det *= matrix_copy(i, i);
}

return det;
}

bool Extrapolator::Consistent(const extrapolator_base_matrix& augment)
{
bool Extrapolator::Consistent(const matrix_t& augment) {
return Determinant() == det_fast(augment);
}

Expand Down Expand Up @@ -97,45 +107,44 @@ Extrapolator::Extrapolator(std::initializer_list<std::vector<T>> dependancy_matr
++r;
}
}
Extrapolator::solution_t Extrapolator::Solve(const ublas::vector<T>& augment) const
Extrapolator::solution_t Extrapolator::Solve(const vector_t& augment) const
{
auto e = *this;
auto e = static_cast<const matrix_t&>(*this);
auto sz1 = size1();
auto sz2 = size2();

ublas::vector<T> a(sz2);
const ublas::vector<T>* au = &augment;
// Initialize vector with size and default value
vector_t a(sz2, Valuable(0));
const vector_t* au = &augment;
if (sz1 > sz2 + 1 /*augment*/) {
// make square matrix to make it solvable by boost ublas
e = Extrapolator(sz2, sz2);
// sum first equations
a[0] = 0;
for (auto i = sz2; i--;) {
e(0, i) = 0;
e.insert_element(0, i, Valuable(0));
}
auto d = sz1 - sz2;
for (auto i = d; i--;) {
for (auto j = sz2; j--;) {
e(0, j) += operator()(i, j);
}
a[0] += augment[i];
a(i - d) = (*au)(i); // Use vector's operator() provided by Boost Ublas for element access
}

for (auto i = d; i < sz1; ++i) {
for (auto j = sz2; j--;) {
e(i - d, j) = operator()(i, j);
}
a[i - d] = augment[i];
a(i - d) = (*au)(i); // Use vector's operator() provided by Boost Ublas for element access
}
au = &a;
}
solution = ublas::solve(e, *au, ublas::upper_tag());
return solution;
}

Extrapolator::T Extrapolator::Determinant() const
{
ublas::permutation_matrix<std::size_t> pivots(this->size1());
Extrapolator::T Extrapolator::Determinant() const {
permutation_matrix_t pivots(this->size1());
auto mLu = *this;
auto isSingular = ublas::lu_factorize(mLu, pivots);
if (isSingular)
Expand All @@ -152,12 +161,11 @@ Extrapolator::T Extrapolator::Determinant() const
return det;
}

bool Extrapolator::Consistent(const ublas::vector<T>& augment)
{
bool Extrapolator::Consistent(const vector_t& augment) {
auto sz = augment.size();
extrapolator_base_matrix augmentedMatrix(sz, 1);
matrix_t augmentedMatrix(sz, 1);
for (auto i = sz; i-- > 0;) {
augmentedMatrix(i, 0) = augment[i];
augmentedMatrix(i, 0) = augment(i);
}
return Consistent(augmentedMatrix);
}
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15 changes: 12 additions & 3 deletions omnn/extrapolator/Extrapolator.h
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ namespace omnn::math {
namespace ublas = boost::numeric::ublas;
//using extrapolator_value_type = a_rational;
using extrapolator_value_type = Valuable;
using extrapolator_base_matrix = boost::numeric::ublas::matrix<extrapolator_value_type>;
using extrapolator_base_matrix = ublas::matrix<extrapolator_value_type>;


class Extrapolator
Expand All @@ -37,21 +37,30 @@ class Extrapolator
mutable solution_t solution;

public:
using vector_t = ublas::vector<T, custom_allocator<T>>;
using matrix_t = ublas::matrix<T, ublas::row_major, custom_allocator<T>>;

using base::base;

Extrapolator() = default;

Extrapolator(std::initializer_list<std::vector<T>> dependancy_matrix);

solution_t Solve(const ublas::vector<T>& augment) const;
solution_t Solve(const vector_t& augment) const;

T Determinant() const;

/**
* If possible, make the matrix consistent
* @return true if it is
* **/
bool Consistent(const ublas::vector<T>& augment);
bool Consistent(const vector_t& augment);

/**
* If possible, make the matrix consistent
* @return true if it is
* **/
bool Consistent(const matrix_t& augment);

/**
* If possible, make the matrix consistent
Expand Down
130 changes: 122 additions & 8 deletions omnn/math/Polyfit.h
Original file line number Diff line number Diff line change
Expand Up @@ -40,16 +40,27 @@ auto polyfit( const std::vector<T>& oX, const std::vector<T>& oY, size_t nDegree
{
using namespace boost::numeric::ublas;

// Define a custom allocator type for the Boost Numeric Ublass types
using custom_alloc_t = custom_allocator<T>;

// Use the custom allocator for the matrix and vector types
using matrix_t = matrix<T, basic_row_major<>, unbounded_array<T, custom_alloc_t>>;
using vector_t = vector<T, unbounded_array<T, custom_alloc_t>>;

// Define a custom allocator type for int
using custom_int_alloc_t = custom_allocator<int>;

// Use the custom allocator for the permutation_matrix type
using permutation_matrix_t = permutation_matrix<int, unbounded_array<int, custom_int_alloc_t>>;
if ( oX.size() != oY.size() )
throw std::invalid_argument( "X and Y vector sizes do not match" );

// more intuitive this way
nDegree++;

auto nCount = oX.size();
matrix<T> oXMatrix( nCount, nDegree );
matrix<T> oYMatrix( nCount, 1 );

matrix_t oXMatrix( nCount, nDegree );
matrix_t oYMatrix( nCount, 1 );
// copy y matrix
for ( size_t i = 0; i < nCount; i++ )
{
Expand All @@ -67,22 +78,125 @@ auto polyfit( const std::vector<T>& oX, const std::vector<T>& oY, size_t nDegree
}
}

// Scale input data
T xMean = std::accumulate(oX.begin(), oX.end(), T(0)) / oX.size();
T xStd = std::sqrt(std::inner_product(oX.begin(), oX.end(), oX.begin(), T(0)) / oX.size() - xMean * xMean);
T yMean = std::accumulate(oY.begin(), oY.end(), T(0)) / oY.size();
T yStd = std::sqrt(std::inner_product(oY.begin(), oY.end(), oY.begin(), T(0)) / oY.size() - yMean * yMean);

std::cout << "Debug: xMean = " << xMean << ", xStd = " << xStd << ", yMean = " << yMean << ", yStd = " << yStd << std::endl;

for (size_t i = 0; i < nCount; ++i) {
for (size_t j = 0; j < nDegree; ++j) {
oXMatrix(i, j) = std::pow(oX[i] - xMean, j) / std::pow(xStd, j);
}
oYMatrix(i, 0) = (oY[i] - yMean) / yStd;
}
// transpose X matrix
matrix<T> oXtMatrix( trans(oXMatrix) );
matrix_t oXtMatrix( trans(oXMatrix) );
// multiply transposed X matrix with X matrix
matrix<T> oXtXMatrix( prec_prod(oXtMatrix, oXMatrix) );
matrix_t oXtXMatrix( prec_prod(oXtMatrix, oXMatrix) );
// multiply transposed X matrix with Y matrix
matrix<T> oXtYMatrix( prec_prod(oXtMatrix, oYMatrix) );
matrix_t oXtYMatrix( prec_prod(oXtMatrix, oYMatrix) );

// Add regularization to handle near-singular matrices
const T lambda = 1e-8; // Adjusted regularization parameter
for (size_t i = 0; i < oXtXMatrix.size1(); ++i) {
oXtXMatrix(i, i) += lambda;
}

std::cout << "Debug: Regularization parameter lambda = " << lambda << std::endl;

// Solve the system using LU decomposition
permutation_matrix<std::size_t> pm(oXtXMatrix.size1());
lu_factorize(oXtXMatrix, pm);
lu_substitute(oXtXMatrix, pm, oXtYMatrix);

std::cout << "Debug: Coefficients:" << std::endl;
for (size_t i = 0; i < oXtYMatrix.size1(); ++i) {
std::cout << oXtYMatrix(i, 0) << " ";
}
std::cout << std::endl;

// Check for near-zero determinant
T det = 1;
for (size_t i = 0; i < oXtXMatrix.size1(); ++i) {
det *= oXtXMatrix(i, i);
}
std::cout << "Debug: Determinant before LU decomposition: " << det << std::endl;

// Check for singularity after regularization
det = 1;
for (size_t i = 0; i < oXtXMatrix.size1(); ++i) {
det *= oXtXMatrix(i, i);
}
std::cout << "Debug: Determinant after regularization: " << det << std::endl;

// Check input data
std::cout << "Debug: Input data (X, Y):" << std::endl;
for (size_t i = 0; i < nCount; ++i) {
std::cout << "(" << oX[i] << ", " << oY[i] << ") ";
}
std::cout << std::endl;

// Scale input data
T x_mean = std::accumulate(oX.begin(), oX.end(), T(0)) / nCount;
T x_std = std::sqrt(std::inner_product(oX.begin(), oX.end(), oX.begin(), T(0)) / nCount - x_mean * x_mean);
T y_mean = std::accumulate(oY.begin(), oY.end(), T(0)) / nCount;
T y_std = std::sqrt(std::inner_product(oY.begin(), oY.end(), oY.begin(), T(0)) / nCount - y_mean * y_mean);

std::vector<T> scaled_oX(oX), scaled_oY(oY);
for (size_t i = 0; i < nCount; ++i) {
scaled_oX[i] = (oX[i] - x_mean) / x_std;
scaled_oY[i] = (oY[i] - y_mean) / y_std;
}

// Tikhonov regularization parameter
// lambda is already declared earlier, so we remove the redeclaration here

// Add regularization term to oXtXMatrix
for (size_t i = 0; i < oXtXMatrix.size1(); ++i) {
oXtXMatrix(i, i) += lambda;
}
// lu decomposition
permutation_matrix<int> pert(oXtXMatrix.size1());
permutation_matrix_t pert(oXtXMatrix.size1());
auto singular = lu_factorize(oXtXMatrix, pert);
// must be singular
std::cout << "Debug: LU factorization result: " << singular << std::endl;

// Check matrix after LU decomposition
std::cout << "Debug: oXtXMatrix after LU decomposition:" << std::endl;
for (size_t i = 0; i < oXtXMatrix.size1(); ++i) {
for (size_t j = 0; j < oXtXMatrix.size2(); ++j) {
std::cout << oXtXMatrix(i, j) << " ";
}
std::cout << std::endl;
}

// must not be singular
BOOST_ASSERT( singular == 0 );

std::cout << "Debug: oXtYMatrix before substitution:" << std::endl;
for (size_t i = 0; i < oXtYMatrix.size1(); ++i) {
std::cout << oXtYMatrix(i, 0) << " ";
}
std::cout << std::endl;
// backsubstitution
lu_substitute(oXtXMatrix, pert, oXtYMatrix);

std::cout << "Debug: Resulting coefficients:" << std::endl;
for (size_t i = 0; i < oXtYMatrix.size1(); ++i) {
std::cout << oXtYMatrix(i, 0) << " ";
}
std::cout << std::endl;

// Unscale the coefficients
for (size_t i = 0; i < oXtYMatrix.size1(); ++i) {
T x_std_power = T(1);
for (size_t j = 0; j < i; ++j) {
x_std_power *= x_std;
}
oXtYMatrix(i, 0) = oXtYMatrix(i, 0) * y_std / x_std_power;
}
// copy the result to coeff
return std::vector<T>( oXtYMatrix.data().begin(), oXtYMatrix.data().end() );
}
Expand Down

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