[petsc-users] EPSViewer in SLEPc

[Kong, Fande]

Hi All,

The EPSViewer in SLEPc looks weird. I do not understand the viewer logic.
For example there is a piece of code in SLEPc (at line 225 of epsview.c):





*    if (!ispower) {      if (!eps->ds) { ierr =
EPSGetDS(eps,&eps->ds);CHKERRQ(ierr); }      ierr =
DSView(eps->ds,viewer);CHKERRQ(ierr);    }*

If eps->ds is NULL, why we are going to create a new one? I just want to
view this object. If it is NULL, you should just show me that this object
is empty. You could print out: ds: null.

If a user wants to develop a new EPS solver, and then register the new EPS
to SLEPc. But the user does not want to use DS, and DSView will show some
error messages:













*[0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------[0]PETSC
ERROR: Object is in wrong state[0]PETSC ERROR: Requested matrix was not
created in this DS[0]PETSC ERROR: See
http://www.mcs.anl.gov/petsc/documentation/faq.html
<http://www.mcs.anl.gov/petsc/documentation/faq.html> for trouble
shooting.[0]PETSC ERROR: Petsc Release Version 3.7.5, unknown [0]PETSC
ERROR: ../../../moose_test-opt on a arch-darwin-c-debug named FN604208 by
kongf Thu Apr  6 14:22:14 2017[0]PETSC ERROR: #1 DSViewMat() line 149 in
/slepc/src/sys/classes/ds/interface/dspriv.c[0]PETSC ERROR: #2
DSView_NHEP() line 47
in/slepc/src/sys/classes/ds/impls/nhep/dsnhep.c[0]PETSC ERROR: #3 DSView()
line 772 in/slepc/src/sys/classes/ds/interface/dsbasic.c[0]PETSC ERROR: #4
EPSView() line 227 in /slepc/src/eps/interface/epsview.c[0]PETSC ERROR: #5
PetscObjectView() line 106 in/petsc/src/sys/objects/destroy.c[0]PETSC
ERROR: #6 PetscObjectViewFromOptions() line 2808 in
/petsc/src/sys/objects/options.c[0]PETSC ERROR: #7 EPSSolve() line 159 in
/slepc/src/eps/interface/epssolve.c*



Fande,
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