Hello Simon, Thank you very much for the suggestion. The Matlab and deal.ii solutions matched with each other after increasing the number of digits written to the std::ofstream object.
Thanks, Krish On Saturday, 29 July 2023 at 20:13:48 UTC+5:30 simon...@gmail.com wrote: > Hi. > > From your attached files it looks like you have saved the matrix and rhs > with quite few digits. Do you get the same result if you increase the > number of digits you write to your std::ofstream object? > > Compare: > https://en.cppreference.com/w/cpp/io/manip/setprecision > > Best, > Simon > > On 29/07/2023 16:36, Krish wrote: > > Hello, > > > > I am solving a problem that has 30 degrees of freedom. The newton update > solution obtained from deal.ii (using both Direct and CG solver) seems to > be less accurate (differs after 4 significant digits) from the newton > update solution obtained from Matlab using the same tangent_matrix and > system_rhs. I am getting the two following solutions from the same > tangent_matrix and system_rhs (data files containing the tangent_matrix and > system_rhs attached). > > > > Matlab solution deal.ii solution > > > > 0 0 > > -0.003033422503555 -0.003033560000000 > > 0 0 > > -0.002439900952733 -0.002439990000000 > > 0 0 > > -0.002737307578376 -0.002737430000000 > > 0.001007226333711 0.001007240000000 > > -0.001069740617723 -0.001069780000000 > > 0.001663965890031 0.001663970000000 > > -0.002605547185476 -0.002605610000000 > > 0.001113032138953 0.001113040000000 > > -0.001469379092482 -0.001469430000000 > > 0.000916401048149 0.000916380000000 > > 0 0 > > 0.001674445763014 0.001674440000000 > > 0 0 > > 0.001041269520982 0.001041260000000 > > -0.000000000000000 -0.000000000000000 > > 0 0 > > 0.003033422503555 0.003033560000000 > > 0 0 > > 0.002439900952733 0.002439990000000 > > 0 0 > > 0.002737307578376 0.002737430000000 > > 0.001007226333711 0.001007240000000 > > 0.001069740617723 0.001069780000000 > > 0.001663965890031 0.001663970000000 > > 0.002605547185476 0.002605610000000 > > 0.001113032138953 0.001113040000000 > > 0.001469379092482 0.001469430000000 > > > > I am trying to figure out what could be the reason behind it and how to > get a more accurate solution. > > > > Thank you in advance. > > > > Krish > > > > -- > > The deal.II project is located at http://www.dealii.org/ < > http://www.dealii.org/> > > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en < > https://groups.google.com/d/forum/dealii?hl=en> > > --- > > You received this message because you are subscribed to the Google > Groups "deal.II User Group" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to dealii+un...@googlegroups.com <mailto: > dealii+un...@googlegroups.com>. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/ac75c294-7b25-4351-82e5-dd7ad3fd410bn%40googlegroups.com > > < > https://groups.google.com/d/msgid/dealii/ac75c294-7b25-4351-82e5-dd7ad3fd410bn%40googlegroups.com?utm_medium=email&utm_source=footer > >. > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/c9abe8af-1931-4cfc-a082-ef249519b7acn%40googlegroups.com.
