code: function() {
              	var v = [];
              	
              	for(var i = 1; i <= this.cols(); i++) {
              	    for(var j = 1; j <= this.rows(); j++) {
              		v.push(this.e(j, i));
              	    }
              	}
  
              	return $V(v);
                  }
docs: unroll a matrix into a vector