Numerical analysis of two Galerkin discretizations with graded temporal grids for fractional evolution equations
Abstract
Two numerical methods with graded temporal grids are analyzed for fractional evolution equations. One is a low-order discontinuous Galerkin (DG) discretization in the case of fractional order 0<α<1, and the other one is a low-order Petrov Galerkin (PG) discretization in the case of fractional order 1<α<2. By a new duality technique, pointwise-in-time error estimates of first-order and (3-α) -order temporal accuracies are respectively derived for DG and PG, under reasonable regularity assumptions on the initial value. Numerical experiments are performed to verify the theoretical results.
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