[FFmpeg-devel] [PATCH] lls: move the Cholesky decomposition in a separate function

Michael Niedermayer michaelni
Sun Nov 1 11:36:39 CET 2009

On Sun, Nov 01, 2009 at 12:54:33AM +0100, Nicolas George wrote:
> Le decadi 10 brumaire, an CCXVIII, Michael Niedermayer a ?crit?:
> > The question i have is, why?
> I intend to isolate the code that can be useful in other context that just
> the LPC computations. The Cholesty decomposition seemed a good place to
> start, since it is a very well defined and delimited part of the code.

In what other context would we want to use it?

> And the comments were really missing for anyone who wanted to understand
> this code.


> > Also you completely rewrite the code during the move, making it much more
> > complex, harder to read (for me) and bigger (in terms of lines of code)
> I rewrote the code to be sure that I really understood it. And in the end, I
> chose to submit my version because it did not have the hardcoded limit on
> the size of the matrice, although I admit it comes at the cost of harder to
> read pointer arithmetic.
> I can re-submit the same with exactly your code if you prefer.
> Or I can write code using a VLA prototype:
> void function(... unsigned n, double m[n][])
> if such code is not frowned upon (it is standard C99 but I expect it may
> make quite a few compilers chock).

Iam not convinced yet that the compile time limit is a problem
so iam not in favor of replacing it by more complex or less portable code.
what is a problem is that this limit that should be internal is in the
public header (it makes changing it tricky ...)


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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