Hey Bruno, Thanks for your reply, that makes sense to me now.
Best, Jiaqi 在 2017年2月22日星期三 UTC-5上午9:13:29，Bruno Turcksin写道： > > Hi, > > while it looks strange I don't think there is any problem. In > plottingBug-0002.png, Visit only knows the value at the four vertices of > the domain and then it tries to "fill" the domain with a possible solution. > In figure1.png, you give Visit the values on 9 points and thus, it has more > information on how to fill the domain. If you compare the two figures, you > can see that the solution on the four vertices is the same. If you use > data_out.build_patches(3), you will get another solution closer to what you > expect. The reason why, it looks good on figure2 is because, like Wolfgang > said, Visit split the domain on triangle and then does a linear > approximation. In case 2, the triangles are aligned with the solution, > while in case 1 there are not (the domain is split in two triangle with a > common edge going from top left to bottom right). > > Best, > > Bruno > > On Wednesday, February 22, 2017 at 8:41:54 AM UTC-5, Jiaqi ZHANG wrote: >> >> Dear Prof. Bangerth, >> >> Thanks for your reply. >> Two figures come from two different Vectors. >> The one that color plot doesn't match the contour plot is Solution1: >> sol[0] = 1.02708; >> sol[1] = 0.00341325; >> sol[2] = 0.0261353; >> sol[3] = 0.00341325; >> sol[4] = -0.0589509; >> sol[5] = 0.0261353; >> >> >> while the other one is Solution2 >> sol[0] = 1.02708; >> sol[1] = -0.00341325; >> sol[2] = 0.0261353; >> sol[3] = 0.00341325; >> sol[4] = 0.0589509; >> sol[5] = 0.0261353; >> Soluiton2 is fine. For Solution1, I checked the result with MATLAB, the >> contour plot is right. >> I also follow your instruction and tried data_out.build_patches(2). For >> Solution2, it is almost >> the same, but Solution1 is very different from that when >> data_out.build_patches() is used. >> By the way, VISIT version is 2.10.3. >> >> >> Thanks, >> Jiaqi >> >> 在 2017年2月21日星期二 UTC-5下午11:39:41，Wolfgang Bangerth写道： >>> >>> On 02/21/2017 09:32 PM, Jiaqi Zhang wrote: >>> > >>> > I am not sure if this is the right place to report this. >>> > >>> > In one of the following figures, the color plot doesn't math the >>> contour plot, >>> > is this the problem with VISIT? >>> >>> Can you explain how the way you created the two figures differ? >>> >>> Visit visualizes things by splitting each quad into two along one of the >>> two >>> diagonals, and then using a linear approximation on each triangle. These >>> do >>> not necessarily correspond to the bilinear function that you are >>> outputting, >>> and may be the difference between the pseudocolor plot and the >>> isocontour plot >>> (neither of which are equal to the P2 function in deal.II). >>> >>> You can probably get a better picture by providing a positive argument >>> to the >>> build_patches() function. >>> >>> Best >>> W. >>> >>> >>> -- >>> ------------------------------------------------------------------------ >>> Wolfgang Bangerth email: bang...@colostate.edu >>> www: >>> http://www.math.colostate.edu/~bangerth/ >>> >>> -- 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. For more options, visit https://groups.google.com/d/optout.
