LeMA/matrices.h

#include <string>
#include <vector>
#include <cassert>

#define assertm(exp, msg) assert((void(msg), exp))

class Matrix{
    private:
        std::vector<std::vector<float>> values;
    public:
        void Randomize();
        void Randomize(float, float);

        void Set(float);

        void Multiply(float);
        Matrix Multiply(Matrix*);

        void Add(float);
        void Add(Matrix*);

        void Substract(float);
        void Substract(Matrix*);

        void Print(std::string_view);

        void Transpose();

        // Constructors
        Matrix(int, int);
        Matrix(Matrix*);
};

// Constructs a zero matrix
Matrix::Matrix(int rows, int cols){
    for(int m = 0; m < rows; m++){
        std::vector<float> buffer = {};
        for(int n = 0; n < cols; n++){
            buffer.push_back(0.0F);
        }
        this->values.push_back(buffer);
    }
}

Matrix::Matrix(Matrix* other){
    this->values = other->values;
}

// Multiply 2 matrices (AxB = this x other)
Matrix Matrix::Multiply(Matrix* other){
    // Resulting size is this->M x other->N
    Matrix result(this->values.size(), other->values[0].size());
    for(int m = 0; m < result.values.size(); m++){
        for(int n = 0; n < result.values[m].size(); n++){
            // Sum multiplications
            float buffer = 0.0F;
            for(int i = 0; i < this->values[0].size(); i++){
                buffer += this->values[m][i] * other->values[i][n];
            }
            result.values[m][n] = buffer;
        }
    }
    return result;
}

// Add 2 matrices
void Matrix::Add(Matrix* other){
    // Matrices need to be the same size
    assertm(this->values.size() == other->values.size() && 
        this->values[0].size() == other->values[0].size(),
        "Matrices need to be the same size");
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] += other->values[m][n];
        }
    }
}

// Substract 2 matrices
void Matrix::Substract(Matrix* other){
    // Matrices need to be the same size
    assertm(this->values.size() == other->values.size() && 
        this->values[0].size() == other->values[0].size(),
        "Matrices need to be the same size");
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] -= other->values[m][n];
        }
    }
}

// Print a matrix in terminal, with a title
void Matrix::Print(std::string_view titre){
    std::cout << titre << std::endl;
    for(int m = 0; m < values.size(); m++){
        std::cout << '|';
        for(int n = 0; n < values[m].size(); n++){
            std::cout << values[m][n] << "|";
        }
        std::cout << std::endl;
    }
}

// Add a constant value to every matrix case
void Matrix::Add(float value){
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] += value;
        }
    }
}

// Substract a constant value to every matrix case
void Matrix::Substract(float value){
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] -= value;
        }
    }
}

// Multiply every matrix case by a given factor
void Matrix::Multiply(float value){
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] *= value;
        }
    }
}

// Set a matrix to a given value
void Matrix::Set(float value){
    this->Multiply(0.0F);
    this->Add(value);
}

// Transpose a matrix
void Matrix::Transpose(){
    std::vector<std::vector<float>> buffer = this->values;
    this->values = {};

    // Invert matrix size
    for(int m = 0; m < buffer[0].size(); m++){
        std::vector<float> row = {};
        for(int n = 0; n < buffer.size(); n++){
            row.push_back(buffer[n][m]);
        }
        this->values.push_back(row);
    }
}

// Randomize a matrix from 0.0F to 10.0F
void Matrix::Randomize(){
    this->Randomize(0.0F, 10.0F);
}

// Randomize a matrix from min to max
void Matrix::Randomize(float min, float max){
    for(int m = 0; m < this->values.size(); m++){
        for(int n = 0; n < this->values[m].size(); n++){
            this->values[m][n] = min + ((float)rand()/(float)(RAND_MAX)) * (max - min);
        }
    }
}