<div><br>Hi,</div>
<div> </div>
<div>regarding qn 4 ie the requirement of VecAssemblyBegin,VecAssemblyEnd, I used VecPlaceArray, VecResetArray to change the values. I did not use Assembly after the 1st time step and it works ok. So that is fine too, right?
</div>
<div> </div>
<div>Thank you!<br> </div>
<div><span class="gmail_quote">On 12/4/06, <b class="gmail_sendername">Satish Balay</b> <<a href="mailto:balay@mcs.anl.gov">balay@mcs.anl.gov</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">On Sun, 3 Dec 2006, Matthew Knepley wrote:<br><br>> > 1. Are petscscaler the same as real nos.? I am writing in double precision
<br>> > or real(8). So are these 2 interchangeable? (same as petscint and integer).<br>><br>> Yes.<br><br>You can check these defines in include/finclude/petscdef.h<br><br>PetscInt -> integer*4<br>PetscScalar -> real*8
<br><br>><br>> > 2. while linking in compaq visual fortran, I get the warning message about<br>> > conflict library with LIBCMT. Is it important or can I just ignore it?<br>><br>> This is determined by your configure. Satish will know better how to control
<br>> it.<br><br>There are some warnings because of the way compqaq f90 tries to<br>workarround some bugs in Visual Studio 6 version of the libraries. It<br>will be fine as long as all code [PETSc & application] is compiled
<br>with the same set of compiler options,<br><br>><br>> > 3. I am writing in f90 free form format. When I modify from fixed f77 format<br>> > to f90, it gives me a lot of error, which seems to be the include file
<br>> > error. So, is it possible to write in f90 format?<br>><br>> Depending on which compiler you use, you might have to give a flag. For g95<br>> it is -ffree-form.<br><br>We'll have to see the error messgaes to determine what the problem is
<br>- however - if you check the PETSc fortran examples - they comply with<br>both fixed and free from syntax.<br><br>> > 4. I am writing a Navier stokes solver and I'm using PETSC to solve the<br>> > poisson eqn. If only the RHS changes with each time step, do I need to call
<br>> ><br>> > VecCreateSeq<br>> > <insert values in RHS b><br>> > VecAssemblyBegin<br>> > VecAssemblyEnd<br>> > VecDestroy<br>> ><br>> > at each time step? I don't think I can (or I should) change values of b
<br>> > after VecAssemblyBegin,VecAssemblyEnd, or can I?<br>><br>> You can just change the values. Call AssemblyBegin/End() after each group<br>> of changes.<br><br>Another note: - If you change values with VecSetValues() - you'll need
<br>to call VecAssemblyBegin,VecAssemblyEnd. However if you do<br>VecGetArray() [or VecGetArrayF0()] - and change values - then you<br>don't need the calls to VecAssembly...<br><br>Satish<br><br></blockquote></div><br>