* Michael Pozhidaev
Hi all!
I'd like to better understand some zypp (maybe libsolv) implementation details. Could anybody help me, please!
The question is as follows: consider we have a couple of packages a and b. Dependencies rules imply that a requires b. Reflecting that clause should be as (not a or b), right?
Yes. See http://en.opensuse.org/openSUSE:Libzypp_satsolver_basics on how to translate package dependencies to SAT rules.
But if a is not chosen for installation b gets freedom to have any value, either true or false without any consequent breaks of a solution.
Correct. If a is not installed, it doesn't matter if b is installed or not. However, if a is installed (not a => false), then b must be installed to give a 'true' result of the equation.
What strategy do zypp use to left the b variable unchanged? I mean left corresponding package uninstalled if it was uninstalled. Is it possible to do that strictly or it always implies some probability?
Equations are solved left-to-right. So if a is not installed, then 'not a' already is true and the 'or' part of the equation does not need to be considered. Hth, Klaus -- SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg) Maxfeldstraße 5, 90409 Nürnberg, Germany -- To unsubscribe, e-mail: zypp-devel+unsubscribe@opensuse.org To contact the owner, e-mail: zypp-devel+owner@opensuse.org