BRIX5

/*

    Inertial Measurement Unit Maths Library

    Copyright (C) 2013-2014  Samuel Cowen

    www.camelsoftware.com

    This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef IMUMATH_MATRIX_HPP

#define IMUMATH_MATRIX_HPP

#include <stdlib.h>

#include <string.h>

#include <stdint.h>

#include <math.h>

#include "vector.h"

namespace imu

{

template <uint8_t N> class Matrix

{

public:

    Matrix()

    {

        _cell = &_cell_data[0];

        memset(_cell, 0, N*N*sizeof(double));

    }

    Matrix(const Matrix &m)

    {

        _cell = &_cell_data[0];

        for (int ij = 0; ij < N*N; ++ij)

        {

            _cell_data[ij] = m._cell_data[ij];

        }

    }

    ~Matrix()

    {

    }

    Matrix& operator=(const Matrix& m)

    {

        for (int ij = 0; ij < N*N; ++ij)

        {

            _cell_data[ij] = m._cell_data[ij];

        }

        return *this;

    }

    Vector<N> row_to_vector(int i) const

    {

        Vector<N> ret;

        for (int j = 0; j < N; j++)

        {

            ret[j] = cell(i, j);

        }

        return ret;

    }

    Vector<N> col_to_vector(int j) const

    {

        Vector<N> ret;

        for (int i = 0; i < N; i++)

        {

            ret[i] = cell(i, j);

        }

        return ret;

    }

    void vector_to_row(const Vector<N>& v, int i)

    {

        for (int j = 0; j < N; j++)

        {

            cell(i, j) = v[j];

        }

    }

    void vector_to_col(const Vector<N>& v, int j)

    {

        for (int i = 0; i < N; i++)

        {

            cell(i, j) = v[i];

        }

    }

    double operator()(int i, int j) const

    {

        return cell(i, j);

    }

    double& operator()(int i, int j)

    {

        return cell(i, j);

    }

    double cell(int i, int j) const

    {

        return _cell_data[i*N+j];

    }

    double& cell(int i, int j)

    {

        return _cell_data[i*N+j];

    }

    Matrix operator+(const Matrix& m) const

    {

        Matrix ret;

        for (int ij = 0; ij < N*N; ++ij)

        {

            ret._cell_data[ij] = _cell_data[ij] + m._cell_data[ij];

        }

        return ret;

    }

    Matrix operator-(const Matrix& m) const

    {

        Matrix ret;

        for (int ij = 0; ij < N*N; ++ij)

        {

            ret._cell_data[ij] = _cell_data[ij] - m._cell_data[ij];

        }

        return ret;

    }

    Matrix operator*(double scalar) const

    {

        Matrix ret;

        for (int ij = 0; ij < N*N; ++ij)

        {

            ret._cell_data[ij] = _cell_data[ij] * scalar;

        }

        return ret;

    }

    Matrix operator*(const Matrix& m) const

    {

        Matrix ret;

        for (int i = 0; i < N; i++)

        {

            Vector<N> row = row_to_vector(i);

            for (int j = 0; j < N; j++)

            {

                ret.cell(i, j) = row.dot(m.col_to_vector(j));

            }

        }

        return ret;

    }

    Matrix transpose()

    {

        Matrix ret;

        for(int x = 0; x < N; x++)

        {

            for(int y = 0; y < N; y++)

            {

                ret.cell(y, x) = cell(x, y);

            }

        }

        return ret;

    }

    Matrix<N-1> minor_matrix(int row, int col)

    {

        int colCount = 0, rowCount = 0;

        Matrix<N-1> ret;

        for(int i = 0; i < N; i++ )

        {

            if( i != row )

            {

                for(int j = 0; j < N; j++ )

                {

                    if( j != col )

                    {

                        ret(rowCount, colCount) = cell(i, j);

                        colCount++;

                    }

                }

                rowCount++;

            }

        }

        return ret;

    }

    double determinant()

    {

        if(N == 1)

            return cell(0, 0);

        float det = 0.0;

        for(int i = 0; i < N; i++ )

        {

            Matrix<N-1> minor = minor_matrix(0, i);

            det += (i%2==1?-1.0:1.0) * cell(0, i) * minor.determinant();

        }

        return det;

    }

    Matrix invert()

    {

        Matrix ret;

        float det = determinant();

        for(int x = 0; x < N; x++)

        {

            for(int y = 0; y < N; y++)

            {

                Matrix<N-1> minor = minor_matrix(y, x);

                ret(x, y) = det*minor.determinant();

                if( (x+y)%2 == 1)

                    ret(x, y) = -ret(x, y);

            }

        }

        return ret;

    }

private:

    double* _cell;

    double  _cell_data[N*N];

};

};

#endif