The Complexity of Indefinite Elliptic Problems with Noisy Data
نویسنده
چکیده
We study the complexity of second-order indeenite elliptic problems ?div(aru) + bu = f (with homogeneous Dirichlet boundary conditions) over a d-dimensional domain , the error being measured in the H 1 (()-norm. The problem elements f belong to the unit ball of W r;p ((), where p 2 2; 1] and r > d=p. Information consists of (possibly-adaptive) noisy evaluations of f , a, or b (or their derivatives). The absolute error in each noisy evaluation is at most. We nd that the nth minimal radius for this problem is proportional to n ?r=d + , and that a noisy nite element method with quadrature (FEMQ), which uses only function values, and not derivatives, is a minimal error algorithm. This noisy FEMQ can be eeciently implemented using multigrid techniques. Using these results, we nd tight bounds on the "-complexity (minimal cost of calculating an "-approximation) for this problem, said bounds depending on the cost c() of calculating a-noisy information value. As an example, if the cost of a-noisy evaluation is c() = ?s (for s > 0), then the complexity is proportional to (1=") d=r+s .
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عنوان ژورنال:
- J. Complexity
دوره 13 شماره
صفحات -
تاریخ انتشار 1997