In fact, each B-spline basis function is non-zero on a few adjacent subintervals and, as a result, B-spline basis functions are quite local. Let U be a set of m + 1 non-decreasing numbers, u. The knots can be considered as division points that subdivide the interval [ u. To define B-spline basis functions, we need one more parameter, the degree of these basis functions, p. The i-th B-spline basis function of degree p, written as N. The above is usually referred to as the Cox-de Boor recursion formula. This definition looks complicated; but, it is not difficult to understand.
In 1989, the Griswold family wasn't so lucky in National Lampoon's Christmas Vacation, the third movie in a franchise that included 1983's inaugural Vacation, 1985's European Vacation and 1997's Vegas Vacation..
Before him, Bill Clinton took a total of 174 days for himself. Another big vacationer was Ronald Reagan, who took a total of 390 days during his time in office. In comparison, Obama has only taken 161 vacation days to date. CBS News. As with past administrations, the White House continues to affirm that the president can do anything while on vacation that he would normally do from the Oval Office. With modern technology, communication is rarely an issue or a major concern for the president.