[petsc-users] Multiple output using one viewer

[Barry Smith]

On Jan 6, 2012, at 6:51 AM, Alexander Grayver wrote:

> On 06.01.2012 13:45, Jed Brown wrote:
>> On Fri, Jan 6, 2012 at 03:09, Alexander Grayver <agrayver at gfz-potsdam.de> wrote:
>> This is not always convinient to store everything in one file, but in some cases I do want to use it. I haven't found any examples on that. Do I have to use FILE_MODE_APPEND and then write? What happens if file doesn't exist?
>> 
>> You just create a viewer and then call MatView(), VecView(), etc, repeatedly for each object you want to put in the file (e.g. once per time step). No need for FILE_MODE_APPEND and unless you want to append to an existing file.
> 
> Ok, that was my meaning to use PetscViewerFileSetName from the beginning since if you have let's say ten different objects (Mat and Vec) and you need to output them at each iteration (time step or frequency for multi-freqs modeling) you need ten viewer objects 

  I don't understand why you need ten viewer objects. Why not just dump all the objects into the one file (creating one Viewer object and never changing its name) one after each other and then in MATLAB read then back in one after the other.

   Barry

> which is not cool I guess, that is why I started to use one viewer and change just a name of the file. 
> And to be honest I don't see any reason why having ten viewers is better than calling PetscViewerFileSetName ten times. 
> 
> Regards,
> Alexander