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j3ml/include/J3ML/LinearAlgebra/Matrices.inl

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C++

#pragma once
/// Template Parameterized (Generic) Matrix Functions.
#include <J3ML/LinearAlgebra/Quaternion.hpp>
#include "J3ML/J3ML.hpp"
namespace J3ML::LinearAlgebra {
template <typename Matrix>
bool InverseMatrix(Matrix &mat, float epsilon)
{
Matrix inversed = Matrix::Identity;
const int nc = std::min<int>(Matrix::Rows, Matrix::Cols);
for (int column = 0; column < nc; ++column)
{
// find the row i with i >= j such that M has the largest absolute value.
int greatest = column;
float greatestVal = std::abs(mat[greatest][column]);
for (int i = column+1; i < Matrix::Rows; i++)
{
float val = std::abs(mat[i][column]);
if (val > greatestVal) {
greatest = i;
greatestVal = val;
}
}
if (greatestVal < epsilon) {
mat = inversed;
return false;
}
// exchange rows
if (greatest != column) {
inversed.SwapRows(greatest, column);
mat.SwapRows(greatest, column);
}
// multiply rows
assert(!Math::EqualAbs(mat[column][column], 0.f, epsilon));
float scale = 1.f / mat[column][column];
inversed.ScaleRow(column, scale);
mat.ScaleRow(column, scale);
// add rows
for (int i = 0; i < column; i++) {
inversed.SetRow(i, inversed.Row(i) - inversed.Row(column) * mat[i][column]);
mat.SetRow(i, mat.Row(i) - mat.Row(column) * mat[i][column]);
}
for (int i = column + 1; i < Matrix::Rows; i++) {
inversed.SetRow(i, inversed.Row(i) - inversed.Row(column) * mat[i][column]);
mat.SetRow(i, mat.Row(i) - mat.Row(column) * mat[i][column]);
}
}
mat = inversed;
return true;
}
/// Computes the LU-decomposition on the given square matrix.
/// @return True if the composition was successful, false otherwise. If the return value is false, the contents of the output matrix are unspecified.
template <typename Matrix>
bool LUDecomposeMatrix(const Matrix &mat, Matrix &lower, Matrix &upper)
{
lower = Matrix::Identity;
upper = Matrix::Zero;
for (int i = 0; i < Matrix::Rows; ++i)
{
for (int col = i; col < Matrix::Cols; ++col)
{
upper[i][col] = mat[i][col];
for (int k = 0; k < i; ++k)
upper[i][col] -= lower[i][k] * upper[k][col];
}
for (int row = i+1; row < Matrix::Rows; ++row)
{
lower[row][i] = mat[row][i];
for (int k = 0; k < i; ++k)
lower[row][i] -= lower[row][k] * upper[k][i];
if (Math::EqualAbs(upper[i][i], 0.f))
return false;
lower[row][i] /= upper[i][i];
}
}
return true;
}
/// Computes the Cholesky decomposition on the given square matrix *on the real domain*.
/// @return True if successful, false otherwise. If the return value is false, the contents of the output matrix are uspecified.
template <typename Matrix>
bool CholeskyDecomposeMatrix(const Matrix &mat, Matrix& lower)
{
lower = Matrix::Zero;
for (int i = 0; i < Matrix::Rows; ++i)
{
for (int j = 0; j < i; ++i)
{
lower[i][j] = mat[i][j];
for (int k = 0; k < j; ++k)
lower[i][j] -= lower[i][j] * lower[j][k];
if (Math::EqualAbs(lower[j][j], 0.f))
return false;
lower[i][j] /= lower[j][j];
}
lower[i][i] = mat[i][i];
if (lower[i][i])
return false;
for (int k = 0; k < i; ++k)
lower[i][i] -= lower[i][k] * lower[i][k];
lower[i][i] = std::sqrt(lower[i][i]);
}
return false;
}
template<typename Matrix>
void SetMatrixRotatePart(Matrix &m, const Quaternion &q) {
// See https://www.geometrictools.com/Documentation/LinearAlgebraicQuaternions.pdf .
assert(q.IsNormalized(1e-3f));
const float x = q.x;
const float y = q.y;
const float z = q.z;
const float w = q.w;
m[0][0] = 1 - 2 * (y * y + z * z);
m[0][1] = 2 * (x * y - z * w);
m[0][2] = 2 * (x * y + y * w);
m[1][0] = 2 * (x * y + z * w);
m[1][1] = 1 - 2 * (x * x + z * z);
m[1][2] = 2 * (y * z - x * w);
m[2][0] = 2 * (x * z - y * w);
m[2][1] = 2 * (y * z + x * w);
m[2][2] = 1 - 2 * (x * x + y * y);
}
/** Sets the top-left 3x3 area of the matrix to the rotation matrix about the X-axis. Elements
outside the top-left 3x3 area are ignored. This matrix rotates counterclockwise if multiplied
in the order M*v, and clockwise if rotated in the order v*M.
@param m The matrix to store the result.
@param angle the rotation angle in radians. */
template<typename Matrix>
void Set3x3PartRotateX(Matrix &m, float angle) {
float sinz, cosz;
sinz = Math::Sin(angle);
cosz = Math::Cos(angle);
m[0][0] = 1.f;
m[0][1] = 0.f;
m[0][2] = 0.f;
m[1][0] = 0.f;
m[1][1] = cosz;
m[1][2] = -sinz;
m[2][0] = 0.f;
m[2][1] = sinz;
m[2][2] = cosz;
}
/** Sets the top-left 3x3 area of the matrix to the rotation matrix about the Y-axis. Elements
outside the top-left 3x3 area are ignored. This matrix rotates counterclockwise if multiplied
in the order M*v, and clockwise if rotated in the order v*M.
@param m The matrix to store the result
@param angle The rotation angle in radians. */
template<typename Matrix>
void Set3x3PartRotateY(Matrix &m, float angle) {
float sinz, cosz;
sinz = Math::Sin(angle);
cosz = Math::Cos(angle);
m[0][0] = cosz;
m[0][1] = 0.f;
m[0][2] = sinz;
m[1][0] = 0.f;
m[1][1] = 1.f;
m[1][2] = 0.f;
m[2][0] = -sinz;
m[2][1] = 0.f;
m[2][2] = cosz;
}
/** Sets the top-left 3x3 area of the matrix to the rotation matrix about the Z-axis. Elements
outside the top-left 3x3 area are ignored. This matrix rotates counterclockwise if multiplied
in the order of M*v, and clockwise if rotated in the order v*M.
@param m The matrix to store the result.
@param angle The rotation angle in radians. */
template<typename Matrix>
void Set3x3PartRotateZ(Matrix &m, float angle) {
float sinz, cosz;
sinz = std::sin(angle);
cosz = std::cos(angle);
m[0][0] = cosz;
m[0][1] = -sinz;
m[0][2] = 0.f;
m[1][0] = sinz;
m[1][1] = cosz;
m[1][2] = 0.f;
m[2][0] = 0.f;
m[2][1] = 0.f;
m[2][2] = 1.f;
}
/** Computes the matrix M = R_x * R_y * R_z, where R_d is the cardinal rotation matrix
about the axis +d, rotating counterclockwise.
This function was adapted from https://www.geometrictools.com/Documentation/EulerAngles.pdf .
Parameters x y and z are the angles of rotation, in radians. */
template<typename Matrix>
void Set3x3PartRotateEulerXYZ(Matrix &m, float x, float y, float z) {
// TODO: vectorize to compute 4 sines + cosines at one time;
float cx = std::cos(x);
float sx = std::sin(x);
float cy = std::cos(y);
float sy = std::sin(y);
float cz = std::cos(z);
float sz = std::sin(z);
m[0][0] = cy * cz;
m[0][1] = -cy * sz;
m[0][2] = sy;
m[1][0] = cz * sx * sy + cx * sz;
m[1][1] = cx * cz - sx * sy * sz;
m[1][2] = -cy * sx;
m[2][0] = -cx * cz * sy + sx * sz;
m[2][1] = cz * sx + cx * sy * sz;
m[2][2] = cx * cy;
}
}