W3C home > Mailing lists > Public > www-style@w3.org > October 2010

Re: Positioned Layout proposal

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Thu, 21 Oct 2010 12:43:38 -0400
Message-ID: <4CC06DBA.1000203@mit.edu>
To: shelby@coolpage.com
CC: www-style list <www-style@w3.org>
On 10/21/10 12:32 PM, Shelby Moore wrote:
> Good point. I am glad we can get some initial thinking about quantification.
>
> The key may be how multi-level hierarchy is handled.  I was supposing it
> is necessary that the hierarchy places some restrictions on combinations,
> as is the case with the CSS box model.

It's reasonably common to have thousands to tens of thousands of 
siblings in the CSS box model.

>> And these are constraints on variables with, typically, positive reals
>> or reals as domains, correct?
>
> I have not yet contemplated how large the per table entry data structure
> is

The question is not of data structure size, but of algorithmic 
complexity.  Most constraint satisfaction algorithms I have been able to 
find seem to assume finite domains for the variables, and have 
complexity at least D^N where N is the number of variables and D is the 
domain size, at first read.  Again, maybe I'm just totally 
misunderstanding them....

But in our case N is order of 1e2--1e5 and D is infinite in theory.  In 
practice, D is order of 2^{30} in Gecko, say.

> but if is less than 1024 bytes, then n = 1024 is less than 1 GB of
> virtual memory (hopefully physical memory)

Per page, yes?

> and let's just ballpark guesstimate on the order of less than Gflops.

Where is this estimate coming from?  What are we measuring, even?  flops 
are operations/second; what does it mean to measure problem complexity 
in flops?

-Boris
Received on Thursday, 21 October 2010 16:44:12 GMT

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