sta-peak/src/linalg/linalg.cpp
2024-11-09 02:09:21 +02:00

364 lines
7.3 KiB
C++

#include <sta/math/linalg/linalg.hpp>
#include <sta/math/utils.hpp>
#include <cstdint>
#include <cmath>
#include <iostream>
#ifdef STA_CORE
#include <sta/debug/debug.hpp>
#include <sta/debug/assert.hpp>
#endif
namespace sta{
namespace math {
namespace linalg {
matrix dot(matrix a, matrix b) {
STA_ASSERT_MSG(a.get_cols() == b.get_rows(), "Matrix dimension mismatch");
uint8_t k = a.get_cols();
uint8_t m = a.get_rows();
uint8_t n = b.get_cols();
matrix output(m, n);
for (uint8_t r = 0; r < m; r++) {
for (uint8_t c = 0; c < n; c++) {
float S = 0;
for (uint8_t h = 0; h < k; h++) {
S += a(r, h) * b(h, c);
}
output.set(r, c, S);
}
}
return output;
};
float norm(matrix m) {
if( m.get_rows() == 1 || m.get_cols() == 1 ){
// apply euclid norm on vector
uint16_t size = m.get_size();
float S = 0;
for(uint8_t i = 0; i < size; i++) {
S += m[i] * m[i];
}
float s = sqrt(S);
return s;
}
float sum = 0;
for(int i=0; i<m.get_rows(); i++) {
for(int j=0; j<m.get_cols(); j++) {
sum += m(i, j)*m(i, j);
}
}
return std::sqrt(sum);
};
matrix normalize(matrix m) {
if( m.get_rows() == 1 || m.get_cols() == 1 ){
// apply euclid normalization to vector
uint16_t size = m.get_size();
float S = 0;
for(uint8_t i = 0; i < size; i++) {
S += m[i] * m[i];
}
float s = fast_inv_sqrt(S);
return m * s;
}
// TODO: implement different matrix normalization techniques
return m * (1/norm(m));
};
matrix cross(matrix a, matrix b) {
STA_ASSERT_MSG(a.get_size() == 3 && b.get_size() == 3, "Input Vectors need to be 3 long");
float d[] = {
a[1]*b[2] - a[2]*b[1],
a[2]*b[0] - a[0]*b[2],
a[0]*b[1] - a[1]*b[0]
};
matrix out(3, 1, d);
return out;
};
matrix skew_symmetric(matrix m) {
STA_ASSERT_MSG( m.get_rows() == 1 && m.get_cols() == 1 , "Input vectors not a vector!");
STA_ASSERT_MSG( m.get_size() == 3, "Input vector needs to be of size 3!");
float d[] = {
0, -m[2], m[1],
m[2], 0, -m[0],
-m[1], m[0], 0
};
matrix output(3, 3, d);
return output;
};
matrix add(matrix a, matrix b) {
STA_ASSERT_MSG( a.get_rows() == b.get_rows() && a.get_cols() == b.get_cols(), "Matrix dimensions mismatch!" );
matrix output = a.clone();
uint16_t size = a.get_size();
for (uint16_t i = 0; i < size; i++) {
output.datafield[i] += b.datafield[i];
}
return output;
};
matrix subtract(matrix a, matrix b) {
STA_ASSERT_MSG( a.get_rows() == b.get_rows() && a.get_cols() == b.get_cols(), "Matrix dimensions mismatch!" );
matrix output = a.clone();
uint16_t size = a.get_size();
for (uint16_t i = 0; i < size; i++) {
output.datafield[i] -= b.datafield[i];
}
return output;
};
matrix dot(matrix m, float s) {
float size = m.get_size();
matrix output = m.clone();
for(uint8_t i = 0; i < size; i++) {
output.datafield[i] *= s;
}
return output;
};
matrix cof(matrix m) {
uint8_t rows = m.get_rows();
uint8_t cols = m.get_cols();
matrix output(rows, cols);
for (uint8_t r = 0; r < rows; r++) {
for (uint8_t c = 0; c < cols; c++) {
float cof;
if( (r+c) % 2 == 0 ) {
cof = 1;
} else {
cof = -1;
}
cof *= m.minor(r, c);
output.set(r, c, cof);
}
}
return output;
};
matrix adj(matrix m) {
matrix output = cof(m).T();
return output;
};
matrix inv(matrix m) {
STA_ASSERT_MSG( m.get_cols() == m.get_rows(), "Matrix not square. Inverse not valid" );
uint8_t size = m.get_cols();
if(size == 1) {
matrix output = m.clone();
output.set(0, 0, 1/output(0, 0));
return output;
}
if(size == 2) {
//return inv_adj(m);
return _inv_char_poly_2x2(m);
}
if(size == 3) {
return inv_adj(m);
}
if(size % 2 == 0) {
return inv_schur_dec(m);
}
return inv_adj(m);
};
matrix inv_adj(matrix m) {
STA_ASSERT_MSG( m.get_cols() == m.get_rows(), "Matrix not square. Inverse not valid" );
float d = m.det();
STA_ASSERT_MSG( d!=0, "Matrix is singular. No inverse could be computed." );
d = 1/d;
matrix a = adj(m);
//a.show_serial();
return a * d;
};
matrix inv_char_poly(matrix m) {
STA_ASSERT_MSG( m.get_cols() == m.get_rows(), "Matrix not square. Inverse not valid" );
uint8_t size = m.get_cols();
if( size == 2 ) {
return _inv_char_poly_2x2(m);
}
if( size == 3 ) {
return _inv_char_poly_3x3(m);
}
// revert to different inv function, if matrix size is not correct
return inv(m);
};
matrix inv_schur_dec(matrix m) {
uint8_t rows = m.get_rows();
uint8_t cols = m.get_cols();
STA_ASSERT_MSG( cols == rows, "Matrix not square. Inverse not valid" );
if( cols % 2 != 0) {
// matrix size not integer, function cant be applied.
return inv(m);
}
float det = m.det();
if(det == 0) {
STA_DEBUG_PRINTLN("Matrix is singular. No inverse could be computed. returned identity");
return matrix();
}
uint8_t sub_size = cols/2;
matrix M_inv(cols, cols);
matrix A = m.get_block(0, 0, sub_size, sub_size);
matrix B = m.get_block(0, sub_size, sub_size, sub_size);
matrix C = m.get_block(sub_size, 0, sub_size, sub_size);
matrix D = m.get_block(sub_size, sub_size, sub_size, sub_size);
matrix D_inv = inv(D);
matrix M_D = A - (B * (D_inv * C));
matrix M_D_inv = inv(M_D);
if(!D_inv.is_valid() || !M_D_inv.is_valid()) {
return matrix();
}
matrix _new_B = ((M_D_inv * (B * D_inv)) * -1 );
matrix _new_C = ((D_inv * (C * M_D_inv)) * -1 );
matrix _new_D = D_inv + (D_inv * (C * (M_D_inv * (B * D_inv))) );
M_inv.set_block(0, 0, M_D_inv);
M_inv.set_block(0, sub_size, _new_B);
M_inv.set_block(sub_size, 0, _new_C);
M_inv.set_block(sub_size, sub_size, _new_D);
return M_inv;
};
matrix _inv_char_poly_3x3(matrix m) {
float det = m.det();
if(det == 0) {
// matrix is singular. Inverse is invalid
STA_DEBUG_PRINTLN("Matrix is singular. No inverse could be computed. returned identity");
return matrix();
}
float a0 = -1/det;
float a1 = (m(2, 1) * m(1, 2)) + (m(1, 0) * m(0, 1)) + (m(2, 0) * m(0, 2)) - (m(0, 0) * m(1, 1)) - (m(0, 0) * m(2, 2)) - (m(1, 1) * m(2, 2));
float a2 = m(0, 0) + m(1, 1) + m(2, 2);
matrix M_2 = m * m;
matrix out = ((matrix::eye(3) * a1 ) + (m * a2) - M_2) * a0;
return out;
};
matrix _inv_char_poly_2x2(matrix m) {
float a0 = (m(0, 0) * m(1, 1)) - (m(1, 0) * m(0, 1));
float a1 = - m(0, 0) - m(1, 1);
if(a0 == 0) {
STA_DEBUG_PRINTLN("matrix is singular. No inverse could be computed. returned identity");
return matrix();
}
float fac = -1/a0;
matrix I = matrix::eye(2);
return linalg::dot( linalg::add( linalg::dot(I, a1), m ) , fac );
}
} // namespace linalg
} // namespace math
} // namespace sta