On Tue, Nov 13, 2012 at 06:35:26PM +0000, Garth N. Wells wrote: > On Mon, Nov 12, 2012 at 8:39 AM, Anders Logg <[email protected]> wrote: > > On Mon, Nov 12, 2012 at 08:37:47AM +0000, Garth N. Wells wrote: > >> On Mon, Nov 12, 2012 at 8:31 AM, Anders Logg <[email protected]> wrote: > >> > On Sun, Nov 11, 2012 at 09:33:01PM +0000, Garth N. Wells wrote: > >> >> On Sun, Nov 11, 2012 at 7:36 PM, Anders Logg <[email protected]> wrote: > >> >> > On Sun, Nov 11, 2012 at 10:22:12AM +0000, Garth N. Wells wrote: > >> >> >> On Fri, Oct 26, 2012 at 6:22 AM, Anders Logg <[email protected]> wrote: > >> >> >> > On Mon, Oct 22, 2012 at 10:32:11AM +0100, Garth N. Wells wrote: > >> >> >> >> We have discussed briefly in the past changing from unsigned int > >> >> >> >> (typedef uint) to std::size_t. Starting to solve some really big > >> >> >> >> problems and some changes in Trilinos make it a good time to bring > >> >> >> >> this up again. Any thoughts or objections to moving to std::size_t > >> >> >> >> from uint? > >> >> >> > > >> >> >> > I think this would be a good idea. > >> >> >> > > >> >> >> > >> >> >> I've started making some unsigned int -> std::size_t changes as I > >> >> >> restructure mesh partitioning. > >> >> >> > >> >> >> > I suggest we keep the uint typedef and make it point to size_t. > >> >> >> > > >> >> >> > >> >> >> I think we should use std::size_t and not uint. std::size_t is > >> >> >> already > >> >> >> a typedef and it conveys an intention: big enough for the largest > >> >> >> array that can be allocated on a machine. Also, it's not a question > >> >> >> of unsigned int or std::size_t - there are places for both. > >> >> > > >> >> > So we will keep dolfin::uint for stuff like component indices and > >> >> > other small integers, and use size_t for everything that can > >> >> > potentially be large? > >> >> > >> >> Yes. I lean towards using 'unsigned int' instead of 'dolfin::uint'. > >> > > >> > Why? To minimize internal typedefs? > >> > > >> > >> Yes. Typing 'unsigned int' in full doesn't bother me. > > > > I don't feel strongly about it, as long as we're consistent. > > > >> >> > How about the Mesh? Should we use size_t for stuff like mesh > >> >> > connectivity? > >> >> > > >> >> > >> >> If it can potentially be big, then it should be std::size_t. > >> > > >> > Is the assumption that global dof numbers need size_t while for local > >> > entity indices (to a process) it's enough with uint? > >> > > >> > >> I would suggest using std::size_t for local indices. > >> > >> I've used unsigned int for things like topological and geometric > >> dimensions, number of connected entities, number of entities per cell, > >> etc. > > > > Is there a performance/memory hit? > > > > There should be no performance hit (some small improvements in places > where we will be able to avoid some copying). > > I've almost finished a transition, with just a few tests to sort out. > It's a bit tricky on the Python side because we can't expose uint and > std::size_t because the two will clash on 32-bit machines. It also > turns out that we have been making assumptions as to the PetscInt type > and the Trilinos int type which can't really justify. > > It will use more memory, but I'll have to test to see how much. I > expect that it's just a price that has to be paid to get to really big > problems. We can reduce the std::size_t usage from what I have now if > we fix some classes. Some data structures are used to store the cell > index, which means that they must be of type std::size_t, and this > propagates to parts of the code where std::size_t is not required. > std::size_t can be unwound to uint step-by-step.
ok. I agree size_t is a necessary transition to get to bigger problems. -- Anders _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
