Hi, Guido, Maybe I have the same experience when I did the mesh refinement by Z-Z error estimator. In my code, the meshes refined by Z-Z error estimator are different to each other to some extent in 32-bit and 64-bit PCs, with the same code and the same mesh generator. So I also think that these is a problem of arithmetic accuracy of PCs.
On Sun, Aug 9, 2009 at 6:40 PM, Guido Kanschat <[email protected]> wrote: > > Christian, > > that may well be, unless they are totally different. > > In optimized mode, numerical operations are performed in a different order. > Therefore, round-off errors may accumulate differently. Now, if the > refinement indicators on the last cell to be refined and on the first not to > be refined are the same in exact arithmetic, they may swap positions > depending on roundoff-errors, and this effect accumulates over several > refinement steps, since then we actually solve different problems. > Nevertheless, qualitatively the meshes should be similar. Is that what you > see? > > Best, > Guido > > Christian Henke wrote: > >> Hi all, >> >> i got two different results with step-13 if i switch debug mode on/off. My >> deal version is 6.2.1. >> >> Best, >> Christian >> >> >> >> ---------------------------------------------------------------- >> Dipl.-Math. Christian Henke Tel.: +49 (0) 5323 72-2968 >> Institut für Mathematik Fax: +49 (0) 5323 72-3601 >> Erzstr. 1 [email protected] <mailto: >> [email protected]> >> 38678 Clausthal-Zellerfeld http://www.math.tu-clausthal.de >> ---------------------------------------------------------------- >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii >> >> > > > > _______________________________________________ > dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii > -- Zhengyong Ren AUG Group, Institute of Geophysics Department of Geoscience, ETH Zurich NO H 47 Sonneggstrasse 5 CH-8092, Zürich, Switzerland Tel: +41 44 633 37561 e-mail: [email protected] Gmail: [email protected]
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