Re: [fonc] Incentives and Metrics for Infrastructure vs. Functionality
On Thu, Jan 03, 2013 at 11:33:53AM -0700, Marcus G. Daniels wrote: On 1/2/13 1:49 AM, Ondřej Bílka wrote: A better example is that you have c code where at several places is code for inserting element into sorted array and using that array. What should you do. CS course taugth us to use red-black tree there. Right? Well not exactly. When one looks how is this code used it discovers that first occurence is shortest path problem so radix heap is appropriate. Second does not use ordering so hash table is more appropriate. Third periodicaly generates webpage from sorted data so keeping new data in separate buffer and calling sort from generating routine looks best. Finally fourth, original contains a comment: /* Used to find closest value to given value. Profiling shown this accounted to 13% of time. As updates are rare (not changed in previous year) using more sophisticated structures than binary search is counterproductive.*/ I imagine a process like this: First create a generic container type, say a Map, for the array and a lookup and traversal routine. If performance matters, profiling will reveal that certain uses are more conspicuous than others. Profiling will reveal that you spend 5% time in insert and 3% time in remove. You spend two weeks optimizing your tree and memory allocator for it. Inspection of those uses will suggest refinement of the Map to drop the traversal and/or lookup routines, and thus diversification of the types to an ordered or unordered sets. Distinguishing between integer and more expensive comparisons might motivate introduction of Patricia trees (for integer sets). And thats exactly a problem I am talking about. Person that writes structures will not notice that what he writes is not needed and introduce much more problems by adding patricia trees etc. A person who uses that structure will not notice that he can do it more effectively without these structures because performance details were abstracted away. Note that in my examples each uses some special property that is not worth abstracting because its quite narrow use case. Maybe I'm losing sight of the question at hand. I'm just saying that going maximally generic at first will motivate appropriate specialization of the abstractions. The opposite approach of specialized inline implementations, built from scratch in different apps or even different modules of the same app has a higher risk of creating frozen accidents. Marcus ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Current topics
On Thu, Jan 03, 2013 at 08:27:53PM -0500, Miles Fidelman wrote: you might want to google biological computing - you'll start finding things like this: http://www.guardian.co.uk/science/blog/2009/jul/24/bacteria-computer (title: Bacteria make computers look like pocket calculators) Computing with solvated linear biopolymers is really disadvantaged in relation to moving electrons, photons, plamons, or flipping spins. You sure have a lot of parallellism, but the linear chain and viscous drag severely limits the possible rate of sampling. Fundamentally you could eventually self-assemble a crystal of ~nm^3 sized cells capable of processing/storing a single bit which would be a provably optimal classical computer. Such a thing would make biology look like infinitesimal beer. Think massively parallel/distributed computation focused on organism level survival and behavior. If you want to program colonies of nano machines (biological or otherwise), you're going to have to start thinking of something a very different kinds of algorithms, running on something a lot more powerful than a small cpu programmed in c. Obviously you need to be able to design emergent behaviour on the edge of chaos, which is resilient/gracefully degrading (it pretty much has to, due to noise floor and device failure) but also nondeterministic. This is something which humans are really terrible at, so they need to figure out how to make machines design such machines. Start thinking billions of actors, running on highly parallel hardware, and we might start approaching what cells do today. (FYI, try googling micro-tubules and you'll find some interesting papers on how these sub-cellular structures just might act like associative arrays :-) You're probably referring to Penrose-Hameroff, which is pretty much kook science. ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Incentives and Metrics for Infrastructure vs. Functionality
On Thu, Jan 03, 2013 at 01:07:55AM +0100, Loup Vaillant-David wrote: On Tue, Jan 01, 2013 at 11:18:29PM +0100, Ondřej Bílka wrote: On Tue, Jan 01, 2013 at 09:12:07PM +0100, Loup Vaillant-David wrote: void latin1_to_utf8(std::string s); Let me guess. They do it to save cycles caused by allocation of new string. instead of std::string utf8_of_latin1(std::string s) or std::string utf8_of_latin1(const std::string s) You may have guessed right. But then, *they* guessed wrong. I often se how people blindly use performance related suggestions. Here it was that passing structure by reference is faster than by value. (which is now sometimes false.) First, the program in which I saw this conversion routine is dead slow anyway. If they really cared about the performance of a few encoding conversion, they should have started by unifying string handling to begin with (there are 6 string types in the program, all actively used, and sometimes converted back and forth). Second, every time the conversion does actually do anything, the utf8 string will be longer than the original one, and require a realloc() anyway (unless they wrote some very clever code, but the overall quality of their monstrosity makes it unlikely). Finally, I often needed to write this: std::string temp = compute_text(); latin1_to_utf8(temp); call_function(temp); Which does not reduce allocations in the slightest, compared to call_function(utf8_of_latin1(compute_text())); My version may even be a bit more amenable to optimisation by the compiler. (In addition to be more readable, I dare say.) So, they *may* have made this move because they cared about performance. A more likely explanation though, is that they simply thought oh, I need to convert some strings to utf8, and transliterated that in C++. They could have thought oh, I need utf8 versions of some strings instead, but that would be functional thinking. Loup. ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Incentives and Metrics for Infrastructure vs. Functionality
On 1/4/13 4:04 AM, Ondrej Bilka wrote: Profiling will reveal that you spend 5% time in insert and 3% time in remove. You spend two weeks optimizing your tree and memory allocator for it. The call tree, accumulating these costs in different parent contexts, when correlated to the fact that (presumably) the containers being acted upon are different containers, can suggest a change to a specialized container type depending on the access pattern... Marcus ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Incentives and Metrics for Infrastructure vs. Functionality
I have been looking at Datomic/Datalog which abstracts away the container entirely and focuses simply on entity, attribute, value + time deltas. In theory, the underlying container(s) could adjust to optimize for typical, and possibly changing, usage patterns. Worth a look and some consideration :-) Alan M. On Fri, Jan 4, 2013 at 7:48 AM, Marcus G. Daniels mar...@snoutfarm.comwrote: On 1/4/13 4:04 AM, Ondrej Bilka wrote: Profiling will reveal that you spend 5% time in insert and 3% time in remove. You spend two weeks optimizing your tree and memory allocator for it. The call tree, accumulating these costs in different parent contexts, when correlated to the fact that (presumably) the containers being acted upon are different containers, can suggest a change to a specialized container type depending on the access pattern... Marcus __**_ fonc mailing list fonc@vpri.org http://vpri.org/mailman/**listinfo/fonchttp://vpri.org/mailman/listinfo/fonc -- *Whatever you can do, or dream you can do, begin it. Boldness has genius, power, and magic in it. Begin it now.* - *Goethe* ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Final STEP progress report?
On 11/7/2012 4:37 PM, Kim Rose wrote: Hello, For those of you interested and waiting -- the NSF (National Science Foundation) funding for the 5-year STEPS project has now finished (we stretched that funding to last for 6 years). The final report on this work will be published and available on our website by the end of this calendar year. It's four days past the end of the calendar year, and I don't see a final report: http://www.vpri.org/html/writings.php Am I looking in the wrong place? Or will it be a few more days until it's published? -- Mathnerd314 ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Final STEP progress report?
It turns out that the due date is actually a due interval that starts Jan 1st and extends for a few months ... so we are working on putting the report together amongst other activities ... Cheers, Alan From: Mathnerd314 mathnerd314@gmail.com To: Fundamentals of New Computing fonc@vpri.org Sent: Friday, January 4, 2013 8:43 AM Subject: Re: [fonc] Final STEP progress report? On 11/7/2012 4:37 PM, Kim Rose wrote: Hello, For those of you interested and waiting -- the NSF (National Science Foundation) funding for the 5-year STEPS project has now finished (we stretched that funding to last for 6 years). The final report on this work will be published and available on our website by the end of this calendar year. It's four days past the end of the calendar year, and I don't see a final report: http://www.vpri.org/html/writings.php Am I looking in the wrong place? Or will it be a few more days until it's published? -- Mathnerd314 ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Final STEP progress report?
Kind of like music starts at 9pm :-) We're all anxious to see the results of your work. Thanks (in advance) for sharing it. On Fri, Jan 4, 2013 at 10:51 AM, Alan Kay alan.n...@yahoo.com wrote: It turns out that the due date is actually a due interval that starts Jan 1st and extends for a few months ... so we are working on putting the report together amongst other activities ... Cheers, Alan From: Mathnerd314 mathnerd314@gmail.com To: Fundamentals of New Computing fonc@vpri.org Sent: Friday, January 4, 2013 8:43 AM Subject: Re: [fonc] Final STEP progress report? On 11/7/2012 4:37 PM, Kim Rose wrote: Hello, For those of you interested and waiting -- the NSF (National Science Foundation) funding for the 5-year STEPS project has now finished (we stretched that funding to last for 6 years). The final report on this work will be published and available on our website by the end of this calendar year. It's four days past the end of the calendar year, and I don't see a final report: http://www.vpri.org/html/writings.php Am I looking in the wrong place? Or will it be a few more days until it's published? -- Mathnerd314 ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Final STEP progress report?
Sliding deadlines very often allow other pursuits to creep in ... Cheers, Alan From: Dale Schumacher dale.schumac...@gmail.com To: Alan Kay alan.n...@yahoo.com; Fundamentals of New Computing fonc@vpri.org Sent: Friday, January 4, 2013 8:59 AM Subject: Re: [fonc] Final STEP progress report? Kind of like music starts at 9pm :-) We're all anxious to see the results of your work. Thanks (in advance) for sharing it. On Fri, Jan 4, 2013 at 10:51 AM, Alan Kay alan.n...@yahoo.com wrote: It turns out that the due date is actually a due interval that starts Jan 1st and extends for a few months ... so we are working on putting the report together amongst other activities ... Cheers, Alan From: Mathnerd314 mathnerd314@gmail.com To: Fundamentals of New Computing fonc@vpri.org Sent: Friday, January 4, 2013 8:43 AM Subject: Re: [fonc] Final STEP progress report? On 11/7/2012 4:37 PM, Kim Rose wrote: Hello, For those of you interested and waiting -- the NSF (National Science Foundation) funding for the 5-year STEPS project has now finished (we stretched that funding to last for 6 years). The final report on this work will be published and available on our website by the end of this calendar year. It's four days past the end of the calendar year, and I don't see a final report: http://www.vpri.org/html/writings.php Am I looking in the wrong place? Or will it be a few more days until it's published? -- Mathnerd314 ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
Re: [fonc] Final STEP progress report?
So, now that the NSF project is finished, does this mean that you are now unbounded by it and can take your research in some new direction that you didn't envision when you started, or are you going to continue exactly on the same path? -Carl Gundel From: fonc-boun...@vpri.org [mailto:fonc-boun...@vpri.org] On Behalf Of Alan Kay Sent: Friday, January 04, 2013 11:51 AM To: Fundamentals of New Computing Subject: Re: [fonc] Final STEP progress report? It turns out that the due date is actually a due interval that starts Jan 1st and extends for a few months ... so we are working on putting the report together amongst other activities ... Cheers, Alan _ From: Mathnerd314 mathnerd314@gmail.com To: Fundamentals of New Computing fonc@vpri.org Sent: Friday, January 4, 2013 8:43 AM Subject: Re: [fonc] Final STEP progress report? On 11/7/2012 4:37 PM, Kim Rose wrote: Hello, For those of you interested and waiting -- the NSF (National Science Foundation) funding for the 5-year STEPS project has now finished (we stretched that funding to last for 6 years). The final report on this work will be published and available on our website by the end of this calendar year. It's four days past the end of the calendar year, and I don't see a final report: http://www.vpri.org/html/writings.php Am I looking in the wrong place? Or will it be a few more days until it's published? -- Mathnerd314 ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc ___ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
