In earlier work we have studied a method for discretization in time of a parabolic problem, which consists of representing the exact solution as an integral in the complex plane and then applying a quadrature formula to this integral. In application to a spatially semidiscrete finite-element version of the parabolic problem, at each quadrature point one then needs to solve a linear algebraic system having a positive-definite matrix with a complex shift. We study iterative methods for such systems, considering the basic and preconditioned versions of first the Richardson algorithm and then a conjugate gradient method. doi:10.1017/S1446181112000107
@article{5248, title = {Iterative solution of shifted positive-definite linear systems arising in a numerical method for the heat equation based on Laplace transformation and quadrature}, journal = {ANZIAM Journal}, volume = {52}, year = {2012}, doi = {10.21914/anziamj.v53i0.5248}, language = {EN}, url = {http://dml.mathdoc.fr/item/5248} }
McLean, William; Thomee, Vidar. Iterative solution of shifted positive-definite linear systems arising in a numerical method for the heat equation based on Laplace transformation and quadrature. ANZIAM Journal, Tome 52 (2012) . doi : 10.21914/anziamj.v53i0.5248. http://gdmltest.u-ga.fr/item/5248/