[Users] Kranc/McLachlan incompatibility

[Ian Hinder]

On 21 Jun 2010, at 18:26, Erik Schnetter wrote:

> The current version of Kranc cannot digest the current version of  
> McLachlan.  The problem is with enforcing the trace A constraint,  
> where the variable At_ij is both read and written -- Kranc does not  
> emit the statement that reads the local variable from the grid  
> function.
>
> The enclosed patch corrects this.  It is somewhat lengthy and not  
> entirely elegant:

I would rather not commit such a patch, especially as I thought that  
the code to do this had already been implemented.  It's possible that  
the code was reverted somehow in a later commit.  Can you check back to

	http://github.com/ianhinder/Kranc/commit/f88dacd7e55e94c64a6cd103c81f9bccdb99601a

and see if that version of Kranc works for you?

> Output assignments for all temporaries, not only for those that are  
> only used in the RHS.  If a temporary is used in a LHS, it may still  
> need to be loaded from a grid function.

This will have a performance hit (the compiler is often not smart  
enough to eliminate these things).

> Add a somewhat complex logic to ensure that each temporary and  
> shortcut is declared only once.
>
> When declaring temporaries, do not declare them as constant, because  
> they may change.

As I said, I thought that the logic was already there to do the right  
thing.  I will have to look into this again.

-- 
Ian Hinder
ian.hinder at aei.mpg.de