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..
Bill Clinton took 174 days at Martha's Vineyard and Jackson Hole, Wyoming, and Ronald Reagan vacationed 349 days at his California ranch over eight years. President Obama is also not the first to cut a vacation short. Reagan did it in 1983, Clinton in 1993 and 1998, and Bush, in 2005, in the wake of Hurricane Katrina.