Dear Wolfgang, Thanks very much for your advice. I definitely should and will follow that. But may I still narrow my question for a clarification (with upcoming complexity), and as a quick question ask if adding the boundary term through cell_rhs +=... (as above, and very similar to step-7 in terms of implementation, with minor modifications for a vector problem) leads it to get recognized as the second (row) component of the BlockVector F (system_rhs.block(1)) at the right hand side of the linear system? I mean are there any other general requirements than adding "fe_face_values[U2]..." to the cell_rhs for this purpose?
Thank you, Ali On Tue, Feb 8, 2022 at 10:19 PM Wolfgang Bangerth <[email protected]> wrote: > On 2/8/22 09:12, Ali Seddiq wrote: > > This is while if I change the pressure, naming it as U2 to another > > scalar field variable , naming it as U1, it works, though I get zero > > iteration for U1, and in fact it does not solve for U1. > > For example if I write: > > > > fe_face_values[U1].value(i, q_point) *... (U1: second scalar variable) > > > > It leads to the error, but if I write: > > fe_face_values[U1].value(i, q_point) *... (U1: first scalar variable) > > > > does a number of iterations for U1 , and 0 iteration (probably also > > meaning no solution) for U2. > > Ali -- we don't know what your code looks like (and even if we did, we > would not have the time to debug it), but the paragraph above suggests > to me that you do not actually understand what the various parts of your > code are doing. > > My suggestion to you is to make sure you have the simplest possible case > that fails. That means that you find out what the difference between U1 > and U2 is, and why one fails and the other does not. In general, I find > that copying the current version of a program to a safe place, and then > slashing everything from it that is not necessary to show the bug is a > valid strategy for debugging. Make the program as small as you can, > since this reduces the number of places where the bug can be. > > Best > W. > > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > 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 a topic in the > Google Groups "deal.II User Group" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/dealii/a9_hHimuNLQ/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/af8b61af-423b-7355-e9ae-4269367a074a%40colostate.edu > . > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/CAGCqmDoBZcTS5Affae3zc6nbFjgsh3-ZNRk7-JPbPrv-8EyN3w%40mail.gmail.com.
