source: inundation/ga/storm_surge/pyvolution/wiki/issues.txt @ 614

OPEN ISSUES:
------------

Issue: Exceptions thrown by Python functions called from C don't get caughts
Background: Have a look at gravity in shallow_water. It calls a C function, gradient, which may throw an exception if arguments are scalars.
However, it doesn't get caught becuase gravity itself is called from within C
Importance: Mid
Suggested Action: Have a look at the calling convention from C (David Beasley)
Status: Unresolved


Issue: Parameters specified in config.py must be tranferred to C code 
and it should be possible to override them when setting up a domain.
Background: N/A
Importance: Mid
Suggested Action: 
          1: Let domain read the config file to provide default values.
          2: Write getters and setters to override them.
          3: Pass pertinent values from domain into the c-extensions.
Status: Unresolved, D+O agreed to do it this way 18/5


Issue: Checkpointing - needs to respect changes in script.


Issue: Adding unknown quantities cause a KeyError.  Known quantities
are given in the list other_quantities, in shallow_water.  Do we want
unknown quantities attached to domain in the future?  If so, it
shouldn't cause a key error.
Importance: low
Suggested Action: 


Issue: The water level can not be less than the bed elevation, as an
assert.  
Importance: Medium
Suggested Action: How about having the functionality that water levels are set
to == the bed elevation, if level < bed elevation.  This will make
setting things up easier.


Issue: Transmissive boundary condition can cause unphysical momentums if
material is not moving out of the domain.
Importance: Med
Suggested Action: Add some sort of warning in (subclass of) Transmissive_boundary 
alerting inflow of material.


        
CLOSED ISSUES:
--------------  

Issue: Second order limiters may cause numerical problems 
manifesting themselves as QNAN (Quiet NANs_ or INF)
Background: The second order gradient limiter is not robust enough - 
especially with shallow water depths. Heighs and momentum are 
limited independently and high speeds may result.
Importance: Mid
Suggested Action: 
          1: Try to incorporate a weighted averaging process between 
          shallow depths and large depths as in the first order scheme.
          2: Look at limiting height and momentum together, by keeping 
          an eye on the speeds 
          (e.g make speed constant across a volume and recompute momentum)
          3: Catch errors resulting from these instabilities as early 
          as possibly and produce and throw an appropriate exception
          4: Make small example that reveals this bug.
Status: 1 succesfully implemented by Ole and Stephen 12/5/4.
        2 Didn't work but using the weighted average for momentums seemed 
        to work well.
        3 and 4 not done.
        June 2004: With the new limiter (item 1 and 2) 3 and 4 are probably 
        not necessary now.



Issue: Tags for specifying boundary conditions should be arbitrary
Background: Domain has the functionality for using arbitrary keys
when associating boundary objects to boundary values.
Triangle, which pmesh is based on, uses integers only.
It would be nice to have mnemonic names for boundaries throughout.
Importance: Mid
Status: Duncan resolved this in early June.




Issue: Checkpointing - needs to always back one timestep up in 
       case output wasn't written
Background:
       Data at latest checkpoint may be incomplete or even corrupted 
       depending on when and how program was stopped.
Importance: Mid
Suggested Action: Always try second latest checkpoint first.
Status: Done (Ole 14/5/4)
              

                
Issue: interpolated_conserved_quantities in shallow_water.py
Background: Was computed by flux functions and used by bed_slope.
It turns out to be unneccessary as conserved quantities at centroid works just as well.
Importance: Mid
Suggested Action: Get rid of it everywhere
Status: Was done when whole things was refactored in April 2004 by OMN