[Developers] patch for fallback in CactusBase/IOUtils

[Tom Goodale]

Hi,

it looks like discussion on this has petered out - Frank, I don't think I 
saw a patch in the end ?

Tom

On Wed, 27 Apr 2005, Thomas Radke wrote:

> Frank Loeffler wrote:
>> Hi,
>> 
>> I wrote a small patch which changes the default behaviour of IOUtils (1D 
>> and 2D output) in the case that the specified slices (default to the 
>> axes/axes planes) are not within the computational domain.
>> 
>> The current behaiviour is to take index 0 in that direction.
>> 
>> This patch changes this to the index of the center of the box in this 
>> direction. This can be changed back to the old behaviour using parameters 
>> for 1D and 2D output. (out_[12d]_fallback_method)
>> 
>> Before I ask to include this patch in Cactus I want to know your opinions 
>> about it:
>> 
>> 1) Do you care about this at all? (It is only changing the fallback.)
>> 2) What do you prefer for default:
>>   a. the old behaviour (zero)
>>   b. the new behaviour (center)
>> 3) Are there any things that I missed? (coding style, bugs ect.)
>
> Hi Frank,
>
> it seems that there are no objections against changing the default
> fallback for choosing the slice center for 1D/2D output from 0 to the
> center of the box if the physical coordinate specified in the parfile
> lies outside the grid.
>
> Introducing a new parameter IO::out_[12]d_fallback_method to choose
> between which fallback to use, and make the "center" method the default,
> would break backwards compatibility though.
> So how about extending the range of the existing index slice center
> parameters instead by a new value which decodes this new behaviour ? It
> would look like this:
>
>  INT out_xline_yi "y-index (from 0) for 1D lines in x-direction,
> overrides IO::out_xline_y" STEERABLE = RECOVER
>  {
>     0:* :: "An index between [0, ny)"
>    -1:  :: "Default to physical coordinate IO::out_xline_y if it is
> within grid bounds, otherwise revert to using 0"
>    -2:  :: "Default to physical coordinate IO::out_xline_y if it is
> within grid bounds, otherwise revert to using the y-center of the box"
>  } -2
>
> Runs recovered from old checkpoints would then still use 0 as slice
> center fallback. And you can even choose the falback method on a
> per-direction basis.
>
>
>