min() {
                var v = this.get(0, 0);
                for (var i = 0; i < this.rows; i++) {
                    for (var j = 0; j < this.columns; j++) {
                        if (this.get(i, j) < v) {
                            v = this.get(i, j);
                        }
                    }
                }
                return v;
            }
Returns the minimum value of the matrix
@return {number}