code: function() {
              	if (!this.isSquare()) { return null; }
              	if (this.cols == 1 && this.rows == 1) { return this.row(1); }
              	if (this.cols == 0 && this.rows == 0) { return 1; }
              	var M = this.toRightTriangular();
              	var det = M.elements[0][0], n = M.elements.length;
              	for (var i = 1; i < n; i++) {
              	    det = det * M.elements[i][i];
              	}
              	return det;
                  }
docs: Returns the determinant for square matrices