clone() {
            var newMatrix = new this.constructor[Symbol.species](this.rows, this.columns);
            for (var row = 0; row < this.rows; row++) {
                for (var column = 0; column < this.columns; column++) {
                    newMatrix.set(row, column, this.get(row, column));
                }
            }
            return newMatrix;
        }
Creates an exact and independent copy of the matrix
@return {Matrix}