Matrix.hpp

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#ifndef ORG_EEROS_MATH_MATRIX_HPP_
#define ORG_EEROS_MATH_MATRIX_HPP_

#include <eeros/core/EEROSException.hpp>
#include "MatrixIndexOutOfBoundException.hpp"

#include <utility>
#include <sstream>
#include <cstdlib>
#include <cmath>

namespace eeros {
    namespace math {
        template < unsigned int M, unsigned int N = 1, typename T = double >
        class Matrix {
        public:
            
            static_assert((M > 1 && N >= 1) || (M >=1 && N > 1), "Matrix dimension must be greater or equal than 1x1!");
            
            using value_type = T;
            
            template < unsigned int IM, unsigned int IN, typename IT >
            class MatrixInitializer {
            public:
                MatrixInitializer(Matrix<IM, IN, IT>& mat, unsigned int index = 0) : mat(mat), index(index) { }
                
                MatrixInitializer<IM, IN, IT> operator,(IT right) {
                    mat(index / N, index % N) = right;
                    return MatrixInitializer<IM, IN, IT>(mat, index + 1);
                }
                
                Matrix<IM, IN, IT>& mat;
                unsigned int index;
            }; // END class MatrixInitializer
            
            /********** Constructors **********/
            
            Matrix() { }
            
            Matrix(const T v) {
                (*this) = v;
            }
            
            template<typename... S>
            Matrix(const S... v) : value{std::forward<const T>(v)...} {
                static_assert(sizeof...(S) == M * N, "Invalid number of constructor arguments!");
            }
            
            /********** Initializing the matrix **********/
            
            void zero() {
                for(unsigned int i = 0; i < M * N; i++) {
                    value[i] = 0;
                }
            }
            
            void eye() {
                zero();
                unsigned int j = (M < N) ? M : N;
                for(unsigned int i = 0; i < j; i++) {
                    (*this)(i, i) = 1;
                }
            }
            
            void fill(T v) {
                (*this) = v;
            }
            
            void rotx(double angle) {
                Matrix<M, N, T>& m = *this;
                if(M == 3 && N == 3) {
                    m(0,0) = 1;
                    m(1,0) = 0;
                    m(2,0) = 0;

                    m(0,1) = 0;
                    m(1,1) = std::cos(angle);
                    m(2,1) = std::sin(angle);

                    m(0,2) = 0;
                    m(1,2) = -std::sin(angle);
                    m(2,2) = std::cos(angle);
                }
                else {
                    throw EEROSException("rotx(double) is only implemented for 3x3 matrices");
                }
            }
            
            void roty(double angle) {
                Matrix<M, N, T>& m = *this;
                if(M == 3 && N == 3) {
                    m(0,0) = std::cos(angle);
                    m(1,0) = 0;
                    m(2,0) = -std::sin(angle);

                    m(0,1) = 0;
                    m(1,1) = 1;
                    m(2,1) = 0;

                    m(0,2) = std::sin(angle);
                    m(1,2) = 0;
                    m(2,2) = std::cos(angle);
                }
                else {
                    throw EEROSException("roty(double) is only implemented for 3x3 matrices");
                }
            }
            
            void rotz(double angle) {
                Matrix<M, N, T>& m = *this;
                if(M == 3 && N == 3) {
                    m(0,0) = std::cos(angle);
                    m(1,0) = std::sin(angle);
                    m(2,0) = 0;

                    m(0,1) = -std::sin(angle);
                    m(1,1) = std::cos(angle);
                    m(2,1) = 0;

                    m(0,2) = 0;
                    m(1,2) = 0;
                    m(2,2) = 1;
                }
                else {
                    throw EEROSException("rotz(double) is only implemented for 3x3 matrices");
                }
            }
            
            MatrixInitializer<M, N, T> operator<<(T right) {
                (*this)[0] = right;
                return MatrixInitializer<M, N, T>(*this, 1);
            }
            
            /********** Element access **********/
            
            const T get(unsigned int m, unsigned int n) const {
                return (*this)(m, n);
            }
            
            Matrix<M, 1, T> getCol(unsigned int n) const {
                Matrix<M, 1, T> col;
                for(unsigned int m = 0; m < M; m++) {
                    col(m, 0) = (*this)(m, n);
                }
                return col;
            }
            
            Matrix<1, N, T> getRow(unsigned int m) const {
                Matrix<1, N, T> row;
                for(unsigned int n = 0; n < N; n++) {
                    row(0, n) = (*this)(m, n);
                }
                return row;
            }
            
            template<unsigned int U, unsigned int V>
            Matrix<U, V, T> getSubMatrix(unsigned int m, unsigned int n) const {
                static_assert(U <= M && V <= N, "Dimension of the sub matrix must be lower or equal than of the origin!");
                if(m + U <= M && n + V <= N) {
                    Matrix<U, V, T> sub;
                    for(unsigned int u = 0; u < U; u++) {
                        for(unsigned int v = 0; v < V; v++) {
                            sub(u, v) = (*this)(m + u, n + v);
                        }
                    }
                    return sub;
                }
                else {
                    throw MatrixIndexOutOfBoundException(m + U - 1, M, n + V - 1, N);
                }
            }
            
            void set(unsigned int m, unsigned int n, T value) {
                (*this)(m, n) = value;
            }
            
            void setCol(unsigned int n, const Matrix<M, 1, T>& col) {
                for(unsigned int m = 0; m < M; m++) {
                    (*this)(m, n) = col(m, 0);
                }
            }
            
            void setRow(unsigned int m, const Matrix<1, N, T>& row) {
                for(unsigned int n = 0; n < N; n++) {
                    (*this)(m, n) = row(0, n);
                }
            }
            
            T& operator()(unsigned int m, unsigned int n) {
                if(m >= 0 && m < M && n >= 0 && n < N) {
                    return value[M * n + m];
                }
                else {
                    throw MatrixIndexOutOfBoundException(m, M, n, N);
                }
            }
            
            const T operator()(unsigned int m, unsigned int n) const {
                if(m >= 0 && m < M && n >= 0 && n < N) {
                    return value[M * n + m];
                }
                else {
                    throw MatrixIndexOutOfBoundException(m, M, n, N);
                }
            }
            
            T& operator()(unsigned int i) {
                if(i >= 0 && i < M * N) {
                    return value[i];
                }
                else {
                    throw MatrixIndexOutOfBoundException(i, M * N);
                }
            }
            
            const T operator()(unsigned int i) const {
                if(i >= 0 && i < M * N) {
                    return value[i];
                }
                else {
                    throw MatrixIndexOutOfBoundException(i, M * N);
                }
            }
            
            T& operator[](unsigned int i) {
                if(i >= 0 && i < M * N) {
                    return value[i];
                }
                else {
                    throw MatrixIndexOutOfBoundException(i, M * N);
                }
            }
            
            const T operator[](unsigned int i) const {
                if(i >= 0 && i < M * N) {
                    return value[i];
                }
                else {
                    throw MatrixIndexOutOfBoundException(i, M * N);
                }
            }
            
            /********** Matrix characteristics **********/
            
            constexpr bool isSquare() const {
                return M == N;
            }
            
            bool isOrthogonal() const {
                Matrix<N, M, T> result, transposed, eye;
                eye.eye();
                transposed = this->transpose();
                result = (*this) * transposed;
                return result == eye;
            }
            
            bool isSymmetric() const {
                return (*this) == this->transpose();
            }
            
            bool isDiagonal() const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if(m != n){
                            if((*this)(m, n) != 0){
                                return false;
                            }
                        }
                    }
                }
                return true;
            }
            
            bool isLowerTriangular() const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if(m < n){
                            if((*this)(m, n) != 0){
                                return false;
                            }
                        }
                    }
                }
                return true;
            }
            
            bool isUpperTriangular() const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if(m > n){
                            if((*this)(m, n) != 0){
                                return false;
                            }
                        }
                    }
                }
                return true;
            }
            
            bool isInvertible() const {
                // non square matrices can't be inverted, if the determinat of a matrix is zero it is not invertible
                return (M == N) && (this->det() != 0);
            }
            
            constexpr unsigned int getNofRows() const {
                return M;
            }
            
            constexpr unsigned int getNofColums() const {
                return N;
            }
            
            constexpr unsigned int size() const {
                return M * N;
            }
            
            unsigned int rank() const {
                unsigned int numberOfNonZeroRows = 0;
                Matrix<M, N, T> temp = (*this);
                temp.gaussRowElimination();
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if(temp(m, n) != 0){
                            numberOfNonZeroRows++;
                            break;
                        }
                    }
                }
                return numberOfNonZeroRows;
            }
            
            T det() const {
                if(M == N) { // Determinat can only be calculated of a square matrix
                    if(M == 2) { // 2x2 matrix
                        return (*this)(0, 0) * (*this)(1, 1) - (*this)(0, 1) * (*this)(1,0);
                    }
                    else if(M == 3) { // 3x3 matrix
                        T det = 0;
                        det = (*this)(0, 0) * (*this)(1, 1) * (*this)(2, 2) +
                              (*this)(0, 1) * (*this)(1, 2) * (*this)(2, 0) +
                              (*this)(0, 2) * (*this)(1, 0) * (*this)(2, 1) -
                              (*this)(0, 2) * (*this)(1, 1) * (*this)(2, 0) -
                              (*this)(0, 0) * (*this)(1, 2) * (*this)(2, 1) -
                              (*this)(0, 1) * (*this)(1, 0) * (*this)(2, 2);
                        return det;
                    }
                    else { // 4x4 and bigger square matrices
                           // Use recurcive laplace formula to calculate the determinat.
                           // For big matrices this method needs a lot of time, this 
                           // could be improved with another algorithm.
                        T det = 0;
                        unsigned int  ignoredRow = 0;
                        for(unsigned int m = 0; m < M; m++) {
                            Matrix<M - 1, N - 1, T> subMatrix;
                            unsigned int x = 0, y = 0;
                            unsigned int a = 0, b = 1;
                            while(a < M) {
                                while(b < N) {
                                    if(a != ignoredRow) {
                                        subMatrix(y, x) = (*this)(a, b);
                                        x++;
                                    }
                                    b++;
                                }
                                b = 1;
                                x = 0;
                                if(a != ignoredRow) {
                                    y++; 
                                }
                                a++;
                            }
                            ignoredRow++;
                            T detSubMatrix = subMatrix.det();
                            if(m % 2 == 0) { // even
                                det = det + (*this)(m, 0) * detSubMatrix;
                            }
                            else { // odd
                                det = det - (*this)(m, 0) * detSubMatrix; 
                            }
                        }
                        return det;
                    }
                }
                else {
                    throw EEROSException("Calculating determinant failed: Matrix must be square"); 
                }
                return 0;
            }
            
            T trace() const {
                T result = 0;
                unsigned int j = (M < N) ? M : N;
                for(unsigned int i = 0; i < j; i++) {
                    result += (*this)(i, i);
                }
                return result;
            }
            
            Matrix<N, M, T> transpose() const {
                Matrix<N, M, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(n, m) = (*this)(m, n);
                    }
                }
                return result;
            }
            
            /********** Base operations **********/
            
            bool operator==(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) != right(m, n))
                            return false;
                    }
                }
                return true;
            }

            bool operator!=(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) != right(m, n)) {
                            return true;
                        }
                    }
                }
                return false;
            }
            
            bool operator<(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) >= right(m, n)) {
                            return false;
                        }
                    }
                }
                return true;
            }
            
            bool operator<=(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) > right(m, n)) {
                            return false;
                        }
                    }
                }
                return true;
            }
            
            bool operator>(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) <= right(m, n)) {
                            return false;
                        }
                    }
                }
                return true;
            }
            
            bool operator>=(const Matrix<M, N, T>& right) const {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        if((*this)(m, n) < right(m, n)) {
                            return false;
                        }
                    }
                }
                return true;
            }
            
            Matrix<M, N, T>& operator=(T right) {
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        (*this)(m, n) = right;
                    }
                }
                return *this;
            }
            
            template < unsigned int K >
            Matrix<M, K, T> operator*(const Matrix<N, K, T> right) const {
                Matrix<M, K, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int k = 0; k < K; k++) {
                        result(m, k) = 0;
                        for(unsigned int n = 0; n < N; n++) {
                            result(m, k) += (*this)(m, n) * right(n, k);
                        }
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator*(T right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m,n) = (*this)(m,n) * right;
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> multiplyElementWise(const Matrix<M, N, T> right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) * right(m, n);
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator+(const Matrix<M, N, T> right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) + right(m, n);
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator+(const T right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) + right;
                    }
                }
                return result;
            }
            
            Matrix<M, N, T>& operator+=(const Matrix<M, N, T> right) {
                (*this) = (*this) + right;
                return (*this);
            }
            
            Matrix<M, N, T> operator-(const Matrix<M, N, T> right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) - right(m, n);
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator-(const T right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) - right;
                    }
                }
                return result;
            }
            
            Matrix<M, N, T>& operator-=(const Matrix<M, N, T> right) {
                (*this) = (*this) - right;
                return (*this);
            }
            
            Matrix<M, N, T> operator-() {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = -(*this)(m, n);
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator/(T right) const {
                Matrix<M, N, T> result;
                for(unsigned int m = 0; m < M; m++) {
                    for(unsigned int n = 0; n < N; n++) {
                        result(m, n) = (*this)(m, n) / right;
                    }
                }
                return result;
            }
            
            Matrix<M, N, T> operator!() const {
                T determinant = this->det();
                if(N != M) {
                    throw EEROSException("Invert failed: matrix not square");
                }
                else if(determinant == 0) {
                    throw EEROSException("Invert failed: determinat of matrix is 0");
                }
                else if(this->isOrthogonal() == true) {
                    return transpose();
                }
                else if(M == 2) { // 2x2 matrix
                    Matrix<M, N, T> result;
                    result(0, 0) =  (*this)(1, 1);
                    result(1, 0) = -(*this)(1, 0);
                    result(0, 1) = -(*this)(0, 1);
                    result(1, 1) =  (*this)(0, 0);
                    return result / determinant;
                }
                else if(M == 3) { // 3x3 matrix
                    Matrix<M, N, T> result;
                    result(0, 0) = (*this)(1, 1) * (*this)(2, 2) - (*this)(1, 2) * (*this)(2, 1);
                    result(1, 0) = (*this)(1, 2) * (*this)(2, 0) - (*this)(1, 0) * (*this)(2, 2);
                    result(2, 0) = (*this)(1, 0) * (*this)(2, 1) - (*this)(1, 1) * (*this)(2, 0);
                    result(0, 1) = (*this)(0, 2) * (*this)(2, 1) - (*this)(0, 1) * (*this)(2, 2);
                    result(1, 1) = (*this)(0, 0) * (*this)(2, 2) - (*this)(0, 2) * (*this)(2, 0);
                    result(2, 1) = (*this)(0, 1) * (*this)(2, 0) - (*this)(0, 0) * (*this)(2, 1);
                    result(0, 2) = (*this)(0, 1) * (*this)(1, 2) - (*this)(0, 2) * (*this)(1, 1);
                    result(1, 2) = (*this)(0, 2) * (*this)(1, 0) - (*this)(0, 0) * (*this)(1, 2);
                    result(2, 2) = (*this)(0, 0) * (*this)(1, 1) - (*this)(0, 1) * (*this)(1, 0);
                    return result / determinant;
                }
                else {
                    // This algorithm needs a lot of time maybe there is a better one?
                    Matrix<M, N, T> result;
                    Matrix<M - 1, N - 1, T> smallerPart;
                    unsigned int ignoredRow = 0, ignoredColum = 0;
                    for(unsigned int m = 0; m < M; m++) {
                        for(unsigned int n = 0; n < N; n++) {
                            unsigned int a = 0, b = 0;
                            // 1. Create "matrix of minors"
                            for(unsigned int u = 0; u < M; u++) {
                                for(unsigned int w = 0; w < N; w++) {
                                    if(u != m && w != n){
                                        smallerPart(a, b) = (*this)(u, w);
                                        b++;
                                        b = b % (N - 1);
                                    }
                                }
                                if(u != m) {
                                    a++;
                                    a = a&(M - 1);
                                }
                            }
                            // 2. Swapp signs 
                            if(m % 2 == 0) {
                                if(n % 2 != 0) {
                                    result(m,n) = -smallerPart.det();
                                }
                                else {
                                    result(m, n) = smallerPart.det();
                                }
                            }
                            else {
                                if(n % 2 != 0){
                                    result(m, n) = smallerPart.det();
                                }
                                else {
                                    result(m, n) = -smallerPart.det();
                                }
                            }
                            // 3. Divide throu det of the original matrix
                            result(m, n) = result(m, n) / determinant;
                        }
                    }
                    // 4. transpose
                    return result.transpose();
                }
            }
            
            /********** Static functions **********/
            
            static Matrix<M, N, T> createRotX(double angle) {
                Matrix<M, N, T> m;
                m.rotx(angle);
                return m;
            }
            
            static Matrix<M, N, T> createRotY(double angle) {
                Matrix<M, N, T> m;
                m.roty(angle);
                return m;
            }
            
            static Matrix<M, N, T> createRotZ(double angle) {
                Matrix<M, N, T> m;
                m.rotz(angle);
                return m;
            }
            
            static Matrix<2, 1, T> createVector2(T x, T y) {
                Matrix<2, 1, T> v;
                v(0) = x;
                v(1) = y;
                return v;
            }
            
            static Matrix<3, 1, T> createVector3(T x, T y, T z) {
                Matrix<3, 1, T> v;
                v(0) = x;
                v(1) = y;
                v(2) = z;
                return v;
            }
            
            static Matrix<M, N, T> createDiag(T v) {
                Matrix<M, N, T> d;
                d.eye();
                return d * v;
            }
            
            static Matrix<3, 3, T> createSkewSymmetric(Matrix<3, 1, T> a) {
                Matrix<3, 3, T> result;
                result(0, 0) =  0;
                result(0, 1) = -a(2);
                result(0, 2) =  a(1);
                result(1, 0) =  a(2);
                result(1, 1) =  0;
                result(1, 2) = -a(0);
                result(2, 0) = -a(1);
                result(2, 1) =  a(0);
                result(2, 2) =  0;
                return result;
            }
            
            static Matrix<3, 1, T> crossProduct(Matrix<3, 1, T> a, Matrix<3, 1, T> b) {
                Matrix<3, 1, T> result;
                result(0, 0) = a(1, 0) * b(2, 0) - a(2, 0) * b(1, 0);
                result(1, 0) = a(2, 0) * b(0, 0) - a(0, 0) * b(2, 0);
                result(2, 0) = a(0, 0) * b(1, 0) - a(1, 0) * b(0, 0); 
                return result;
            }
            
            /********** Helper functions **********/
            
            void gaussRowElimination() {
                unsigned int completedColum = 0, completedRow = 0;
                unsigned int checkingRow = 0, rootRow = 0;
                T rowFactor = 0;
                
                sortForGaussAlgorithm();
                while(completedColum < N) {
                    rootRow = completedRow;
                    checkingRow = rootRow + 1;
                    while(checkingRow < M && (*this)(rootRow, completedColum) != 0) {
                        if((*this)(checkingRow, completedColum) != 0) {
                            rowFactor = (*this)(checkingRow, completedColum) / (*this)(rootRow, completedColum); 
                            for(unsigned int n = completedColum; n < N; n++) {
                                (*this)(checkingRow, n) = (*this)(checkingRow, n) - rowFactor * (*this)(rootRow, n);
                            }
                        }
                        checkingRow++;
                    }
                    completedRow++;
                    completedColum++;
                }
            }
            
            void sortForGaussAlgorithm() {
                unsigned int completedColum = 0, completedRow = 0;
                unsigned int swapRow = completedRow + 1;
                
                while(completedColum < N) {
                    while(completedRow < M) {
                        if((*this)(completedRow, completedColum) == 0 && swapRow < M && completedRow < M - 1) {
                            swapRows(completedRow, swapRow);
                            swapRow++;
                        }
                        else {
                            completedRow++; 
                        }
                  }
                  completedColum++;
                  swapRow = completedRow + 1;
                }
            }
            
            void swapRows(unsigned int rowA, unsigned int rowB) {
                for(unsigned int n = 0; n < N; n++) {
                    T t = (*this)(rowA, n);
                    (*this)(rowA, n) = (*this)(rowB, n);
                    (*this)(rowB, n) =  t;
                }
            }
            
        protected:
            T value[M * N];
            
        }; // END class Matrix
        
        /********** Operators **********/
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        Matrix<M, N, T> operator+(T left, Matrix<M, N, T> right) {
            Matrix<M, N, T> result;
            for(unsigned int m = 0; m < M; m++) {
                for(unsigned int n = 0; n < N; n++) {
                    result(m, n) = left + right(m, n);
                }
            }
            return result;
        }
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        Matrix<M, N, T> operator-(T left, Matrix<M, N, T> right) {
            Matrix<M, N, T> result;
            for(unsigned int m = 0; m < M; m++) {
                for(unsigned int n = 0; n < N; n++) {
                    result(m, n) = left - right(m, n);
                }
            }
            return result;
        }
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        Matrix<M, N, T> operator-(const Matrix<M, N, T> &right) {
            Matrix<M, N, T> result;
            for(unsigned int m = 0; m < M; m++) {
                for(unsigned int n = 0; n < N; n++) {
                    result(m, n) = -right(m, n);
                }
            }
            return result;
        }
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        Matrix<M, N, T> operator*(T left, Matrix<M, N, T> right) {
            Matrix<M, N, T> result;
            for(unsigned int m = 0; m < M; m++) {
                for(unsigned int n = 0; n < N; n++) {
                    result(m, n) = left * right(m, n);
                }
            }
            return result;
        }
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        Matrix<M, N, T> operator/(T left, Matrix<M, N, T> right) {
            Matrix<M, N, T> result;
            for(unsigned int m = 0; m < M; m++) {
                for(unsigned int n = 0; n < N; n++) {
                    result(m, n) = left / right(m, n);
                }
            }
            return result;
        }
        
        /********** Print functions **********/
        
        template < unsigned int M, unsigned int N = 1, typename T = double >
        std::ostream& operator<<(std::ostream& os, const Matrix<M, N, T>& right) {
            if(N > 1) os << "[ ";
            for(unsigned int n = 0; n < N; n++) {
                os << '[';
                for(unsigned int m = 0; m < M; m++) {
                    os << right(m, n);
                    if(m < M - 1) os << ' ';
                }
                os << "]' ";
            }
            if(N > 1) os << "]";
            return os;
        }
        
        /********** Type definitions **********/
        
        typedef Matrix<2,1> Vector2;
        typedef Matrix<3,1> Vector3;
        typedef Matrix<4,1> Vector4;
        
        template < unsigned int M, typename T = double >
        using Vector = Matrix<M, 1, T>;
        
        /********** Specialization for a 1x1 matrix **********/
        
        template < typename T >
        class Matrix<1, 1, T> {
            
        public:
            
            using value_type = T;
            
            Matrix() { }
            
            Matrix(const T v) { value = v; }
            
            void zero() { value = 0; }
            
            void eye() { value = 1; }
            
            void fill(T v) { value = v; }
            
            const T get(uint8_t m, uint8_t n) const { return (*this)(m, n); }
            
            Matrix<1, 1, T> getCol(uint8_t n) const { return (*this); }
            
            Matrix<1, 1, T> getRow(uint8_t m) const { return (*this); }
            
            void set(uint8_t m, uint8_t n, T value) { (*this)(m, n) = value; }
            
            T& operator()(uint8_t m, uint8_t n) { if(m == 0 && n == 0) return value; else throw MatrixIndexOutOfBoundException(m, 1, n, 1); }
            
            const T operator()(uint8_t m, uint8_t n) const { if(m == 0 && n == 0) return value; else throw MatrixIndexOutOfBoundException(m, 1, n, 1); }
            
            T& operator()(unsigned int i) { if(i == 0) return value; else throw MatrixIndexOutOfBoundException(i, 1); }
            
            const T operator()(unsigned int i) const { if(i == 0) return value; else throw MatrixIndexOutOfBoundException(i, 1); }
            
            T& operator[](unsigned int i) { if(i == 0) return value; else throw MatrixIndexOutOfBoundException(i, 1); }
            
            const T operator[](unsigned int i) const { if(i == 0) return value; else throw MatrixIndexOutOfBoundException(i, 1); }
            
            constexpr bool isSquare() const { return true; }
            
            bool isOrthogonal() const { return value == 1; }
            
            constexpr bool isSymmetric() const { return true; }
            
            constexpr bool isDiagonal() const { return true; }
            
            constexpr bool isLowerTriangular() const { return true; }
            
            constexpr bool isUpperTriangular() const { return true; }
            
            bool isInvertible() const { return value != 0; }
            
            constexpr unsigned int getNofRows() const { return 1; }
            
            constexpr unsigned int getNofColums() const { return 1; }
            
            constexpr unsigned int size() const { return 1; }
            
            unsigned int rank() const { return (value == 0) ? 1 : 0; }
            
            T det() const { return value; }
            
            T trace() const { return value; }
            
            Matrix<1, 1, T> operator!() const { Matrix<1, 1, T> inv(1/value); return inv; }
            
            operator T() const { return value; }
            
        protected:
            T value;
        };
        
    } // END namespace math
} // END namespache eeros

#endif /* ORG_EEROS_MATH_MATRIX_HPP_ */