Search Results

Search found 56456 results on 2259 pages for 'set theory'.

Page 27/2259 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >

  • Is there a perfect algorithm for chess?

    - by Overflown
    Dear Stack Overflow community, I was recently in a discussion with a non-coder person on the possibilities of chess computers. I'm not well versed in theory, but think I know enough. I argued that there could not exist a deterministic Turing machine that always won or stalemated at chess. I think that, even if you search the entire space of all combinations of player1/2 moves, the single move that the computer decides upon at each step is based on a heuristic. Being based on a heuristic, it does not necessarily beat ALL of the moves that the opponent could do. My friend thought, to the contrary, that a computer would always win or tie if it never made a "mistake" move (however do you define that?). However, being a programmer who has taken CS, I know that even your good choices - given a wise opponent - can force you to make "mistake" moves in the end. Even if you know everything, your next move is greedy in matching a heuristic. Most chess computers try to match a possible end game to the game in progress, which is essentially a dynamic programming traceback. Again, the endgame in question is avoidable though. -- thanks, Allan Edit: Hmm... looks like I ruffled some feathers here. That's good. Thinking about it again, it seems like there is no theoretical problem with solving a finite game like chess. I would argue that chess is a bit more complicated than checkers in that a win is not necessarily by numerical exhaustion of pieces, but by a mate. My original assertion is probably wrong, but then again I think I've pointed out something that is not yet satisfactorily proven (formally). I guess my thought experiment was that whenever a branch in the tree is taken, then the algorithm (or memorized paths) must find a path to a mate (without getting mated) for any possible branch on the opponent moves. After the discussion, I will buy that given more memory than we can possibly dream of, all these paths could be found.

    Read the article

  • What is a data structure for quickly finding non-empty intersections of a list of sets?

    - by Andrey Fedorov
    I have a set of N items, which are sets of integers, let's assume it's ordered and call it I[1..N]. Given a candidate set, I need to find the subset of I which have non-empty intersections with the candidate. So, for example, if: I = [{1,2}, {2,3}, {4,5}] I'm looking to define valid_items(items, candidate), such that: valid_items(I, {1}) == {1} valid_items(I, {2}) == {1, 2} valid_items(I, {3,4}) == {2, 3} I'm trying to optimize for one given set I and a variable candidate sets. Currently I am doing this by caching items_containing[n] = {the sets which contain n}. In the above example, that would be: items_containing = [{}, {1}, {1,2}, {2}, {3}, {3}] That is, 0 is contained in no items, 1 is contained in item 1, 2 is contained in itmes 1 and 2, 2 is contained in item 2, 3 is contained in item 2, and 4 and 5 are contained in item 3. That way, I can define valid_items(I, candidate) = union(items_containing[n] for n in candidate). Is there any more efficient data structure (of a reasonable size) for caching the result of this union? The obvious example of space 2^N is not acceptable, but N or N*log(N) would be.

    Read the article

  • Is there a term for this concept, and does it exist in a static-typed language?

    - by Strilanc
    Recently I started noticing a repetition in some of my code. Of course, once you notice a repetition, it becomes grating. Which is why I'm asking this question. The idea is this: sometimes you write different versions of the same class: a raw version, a locked version, a read-only facade version, etc. These are common things to do to a class, but the translations are highly mechanical. Surround all the methods with lock acquires/releases, etc. In a dynamic language, you could write a function which did this to an instance of a class (eg. iterate over all the functions, replacing them with a version which acquires/releases a lock.). I think a good term for what I mean is 'reflected class'. You create a transformation which takes a class, and returns a modified-in-a-desired-way class. Synchronization is the easiest case, but there are others: make a class immutable [wrap methods so they clone, mutate the clone, and include it in the result], make a class readonly [assuming you can identify mutating methods], make a class appear to work with type A instead of type B, etc. The important part is that, in theory, these transformations make sense at compile-time. Even though an ActorModel<T> has methods which change depending on T, they depend on T in a specific way knowable at compile-time (ActorModel<T> methods would return a future of the original result type). I'm just wondering if this has been implemented in a language, and what it's called.

    Read the article

  • When to use CTEs to encapsulate sub-results, and when to let the RDBMS worry about massive joins.

    - by IanC
    This is a SQL theory question. I can provide an example, but I don't think it's needed to make my point. Anyone experienced with SQL will immediately know what I'm talking about. Usually we use joins to minimize the number of records due to matching the left and right rows. However, under certain conditions, joining tables cause a multiplication of results where the result is all permutations of the left and right records. I have a database which has 3 or 4 such joins. This turns what would be a few records into a multitude. My concern is that the tables will be large in production, so the number of these joined rows will be immense. Further, heavy math is performed on each row, and the idea of performing math on duplicate rows is enough to make anyone shudder. I have two questions. The first is, is this something I should care about, or will SQL Server intelligently realize these rows are all duplicates and optimize all processing accordingly? The second is, is there any advantage to grouping each part of the query so as to get only the distinct values going into the next part of the query, using something like: WITH t1 AS ( SELECT DISTINCT... [or GROUP BY] ), t2 AS ( SELECT DISTINCT... ), t3 AS ( SELECT DISTINCT... ) SELECT... I have often seen the use of DISTINCT applied to subqueries. There is obviously a reason for doing this. However, I'm talking about something a little different and perhaps more subtle and tricky.

    Read the article

  • Silverlight -RIA Services-This EntitySet of type <> does not support the 'Add' operation.

    - by user289082
    In Silverlight project I have this exception when I tried to Add a new object to a DataGrid when a button is clicked. In the DomainService class.. I know I have to implement the Add operation for the new Entity I'm putting, but how can I do that? I mean I did the class, the get method but how do I do the insert operation, I can't see my class in this.ObjectContext, so to whom I would be adding this new object, I have the next fragments of code: public partial class SisPer { [Key] public int Id { get; set; } public string Nombre_Sistema { get; set; } public string Nombre_Perfil { get; set; } public string Nivel { get; set; } public bool Estatus { get; set; } } public IQueryable<SisPer> Get_SisPer() { var query = from per in this.ObjectContext.Cat_Perfil join sis in this.ObjectContext.Cat_Sistema on per.Cat_Sistema.Id equals sis.Id select new SisPer() { Id = per.Id, Nombre_Sistema = sis.Nombre, Nombre_Perfil = per.Nombre, Nivel = per.Nivel, Estatus = per.Estatus }; return query; } public void InsertSisPer(SisPer sisper) { ?? I can't see this.ObjectContext.AddToSisPer(); } Plz Help!!

    Read the article

  • Custom iterator for a class based on two sets

    - by Dan Hook
    I have a class that contains two sets. They both contain the same key type but have different compare operations. I would like to provide an iterator for the class that iterates through the elements of both sets. I want to start with one set, then when I increment an iterator pointing to the last element of the first set, I want to go to the first element of the second set. How do I do this? I would like to preserve the bidirectional iterator semantics of std::set, but if it turns out that implementing a forward iterator is much easier, so be it. I'm willing to use the Boost Iterator library if that would help.

    Read the article

  • assignment vs std::swap and merging and keeping duplicates in seperate object

    - by rubenvb
    Say I have two std::set<std::string>s. The first one, old_options, needs to be merged with additional options, contained in new_options. I can't just use std::merge (well, I do, but not only that) because I also check for doubles and warn the user about this accordingly. To this effect, I have void merge_options( set<string> &old_options, const set<string> &new_options ) { // find duplicates and create merged_options, a stringset containing the merged options // handle duplicated the way I want to // ... old_options = merged_options; } Is it better to use std::swap( merged_options, old_options ); or the assignment I have? Is there a better way to filter duplicates and return the merged set than consecutive calls to std::set_intersection and std::set_union to detect dupes and merge the sets? I know it's slower than one traversal and doing both at once, but these sets are small (performance is not critical) and I trust the Standard more than I trust myself.

    Read the article

  • How to select the first ocurrence in the auto-completion menu by pressing Enter?

    - by janoChen
    Every time there's is a pop up menu. I select the first occurrence and press enter but nothing happens (the word is not completed with he selected occurrence). The only way is to press Tab until you reach the term for a second time. Is there a way of selecting the first occurrence pressing Enter (or other Vim hotkey)? My .vimrc: " SHORTCUTS nnoremap <F4> :set filetype=html<CR> nnoremap <F5> :set filetype=php<CR> nnoremap <F3> :TlistToggle<CR> " press space to turn off highlighting and clear any message already displayed. nnoremap <silent> <Space> :nohlsearch<Bar>:echo<CR> " set buffers commands nnoremap <silent> <M-F8> :BufExplorer<CR> nnoremap <silent> <F8> :bn<CR> nnoremap <silent> <S-F8> :bp<CR> " open NERDTree with start directory: D:\wamp\www nnoremap <F9> :NERDTree /home/alex/www<CR> " open MRU nnoremap <F10> :MRU<CR> " open current file (silently) nnoremap <silent> <F11> :let old_reg=@"<CR>:let @"=substitute(expand("%:p"), "/", "\\", "g")<CR>:silent!!cmd /cstart <C-R><C-R>"<CR><CR>:let @"=old_reg<CR> " open current file in localhost (default browser) nnoremap <F12> :! start "http://localhost" file:///"%:p""<CR> " open Vim's default Explorer nnoremap <silent> <F2> :Explore<CR> nnoremap <C-F2> :%s/\.html/.php/g<CR> " REMAPPING " map leader to , let mapleader = "," " remap ` to ' nnoremap ' ` nnoremap ` ' " remap increment numbers nnoremap <C-kPlus> <C-A> " COMPRESSION function Js_css_compress () let cwd = expand('<afile>:p:h') let nam = expand('<afile>:t:r') let ext = expand('<afile>:e') if -1 == match(nam, "[\._]src$") let minfname = nam.".min.".ext else let minfname = substitute(nam, "[\._]src$", "", "g").".".ext endif if ext == 'less' if executable('lessc') cal system( 'lessc '.cwd.'/'.nam.'.'.ext.' &') endif else if filewritable(cwd.'/'.minfname) if ext == 'js' && executable('closure-compiler') cal system( 'closure-compiler --js '.cwd.'/'.nam.'.'.ext.' > '.cwd.'/'.minfname.' &') elseif executable('yuicompressor') cal system( 'yuicompressor '.cwd.'/'.nam.'.'.ext.' > '.cwd.'/'.minfname.' &') endif endif endif endfunction autocmd FileWritePost,BufWritePost *.js :call Js_css_compress() autocmd FileWritePost,BufWritePost *.css :call Js_css_compress() autocmd FileWritePost,BufWritePost *.less :call Js_css_compress() " GUI " taglist right side let Tlist_Use_Right_Window = 1 " hide tool bar set guioptions-=T "remove scroll bars set guioptions+=LlRrb set guioptions-=LlRrb " set the initial size of window set lines=46 columns=180 " set default font set guifont=Monospace " set guifont=Monospace\ 10 " show line number set number " set default theme colorscheme molokai-2 " encoding set encoding=utf-8 setglobal fileencoding=utf-8 bomb set fileencodings=ucs-bom,utf-8,latin1 " SCSS syntax highlight au BufRead,BufNewFile *.scss set filetype=scss " LESS syntax highlight syntax on au BufNewFile,BufRead *.less set filetype=less " Haml syntax highlight "au! BufRead,BufNewFile *.haml "setfiletype haml " Sass syntax highlight "au! BufRead,BufNewFile *.sass "setfiletype sass " set filetype indent filetype indent on " for snipMate to work filetype plugin on " show breaks set showbreak=-----> " coding format set tabstop=4 set shiftwidth=4 set linespace=1 " CONFIG " set location of ctags let Tlist_Ctags_Cmd='D:\ctags58\ctags.exe' " keep the buffer around when left set hidden " enable matchit plugin source $VIMRUNTIME/macros/matchit.vim " folding set foldmethod=marker set foldmarker={,} let g:FoldMethod = 0 map <leader>ff :call ToggleFold()<cr> fun! ToggleFold() if g:FoldMethod == 0 exe 'set foldmethod=indent' let g:FoldMethod = 1 else exe 'set foldmethod=marker' let g:FoldMethod = 0 endif endfun " save and restore folds when a file is closed and re-opened "au BufWrite ?* mkview "au BufRead ?* silent loadview " auto-open NERDTree everytime Vim is invoked au VimEnter * NERDTree /home/alex/www " set omnicomplete autocmd FileType python set omnifunc=pythoncomplete#Complete autocmd FileType javascript set omnifunc=javascriptcomplete#CompleteJS autocmd FileType html set omnifunc=htmlcomplete#CompleteTags autocmd FileType css set omnifunc=csscomplete#CompleteCSS autocmd FileType xml set omnifunc=xmlcomplete#CompleteTags autocmd FileType php set omnifunc=phpcomplete#CompletePHP autocmd FileType c set omnifunc=ccomplete#Complete " Remove trailing white-space once the file is saved au BufWritePre * silent g/\s\+$/s/// " Use CTRL-S for saving, also in Insert mode noremap <C-S> :update!<CR> vnoremap <C-S> <C-C>:update!<CR> inoremap <C-S> <C-O>:update!<CR> " DEFAULT set nocompatible source $VIMRUNTIME/vimrc_example.vim "source $VIMRUNTIME/mswin.vim "behave mswin " disable creation of swap files set noswapfile " no back ups wwhile editing set nowritebackup " disable creation of backups set nobackup " no file change pop up warning autocmd FileChangedShell * echohl WarningMsg | echo "File changed shell." | echohl None set diffexpr=MyDiff() function MyDiff() let opt = '-a --binary ' if &diffopt =~ 'icase' | let opt = opt . '-i ' | endif if &diffopt =~ 'iwhite' | let opt = opt . '-b ' | endif let arg1 = v:fname_in if arg1 =~ ' ' | let arg1 = '"' . arg1 . '"' | endif let arg2 = v:fname_new if arg2 =~ ' ' | let arg2 = '"' . arg2 . '"' | endif let arg3 = v:fname_out if arg3 =~ ' ' | let arg3 = '"' . arg3 . '"' | endif let eq = '' if $VIMRUNTIME =~ ' ' if &sh =~ '\<cmd' let cmd = '""' . $VIMRUNTIME . '\diff"' let eq = '"' else let cmd = substitute($VIMRUNTIME, ' ', '" ', '') . '\diff"' endif else let cmd = $VIMRUNTIME . '\diff' endif silent execute '!' . cmd . ' ' . opt . arg1 . ' ' . arg2 . ' > ' . arg3 . eq endfunction

    Read the article

  • trying to set and use a password via commandline using ultraVNC on windows server 2003 vnc

    - by mustafa
    Okay, so I installed ultravnc on windows server 2003. It uses the ultravnc.i.i file to store password and configuration information. But I'd like to be able to set the password using the command line. There is a tool called vncpwd: http://www.sysworksoft.net/products/vncpwd.html But it's old, and when you use it to change the password, it changes the password in the system registry instead of the ultravnc.ini file. But, you can set ultravnc to use the registry instead of the ini file. Success? No. I set ultravnc to use the registry (which stores the hashed password that I set using vncpwd), but, it still uses the password in the .ini file. does anyone know what gives.

    Read the article

  • Need Info on the Hidden Switch in SET - "/S" How to implement

    - by ttyl
    I am having some problems doing a proper search of "SET/S" or "SET /S" on google and other search providers. The difficulty arises with the SLASH "/", it is commonly used in search engines to add a "nearness" to the search parameter. I have found no way to escape the SLASH when searching for a SLASH. For those on this community, try searching this domain with the two search terms listed above. It just doesn't work, it ends up looking for SET S instead. But I digress. So Im asking the uber-guru's on this board to help me find out about the documentation of /S and how to implement SET /S in a batch file. SET is an internal DOS/cmd commandand allows many things incuding prompting the user, integer math and writing environment strings. in looking at this link: http://www.robvanderwoude.com/os2set.php it appears that the /S is only for OS2 but im thinking that this might not be the case, due to this: http://www.dostips.com/forum/viewtopic.php?t=2704, apparently used with substings and macros. any help is much appreciated

    Read the article

  • Word 2003 set styles won't convert over when opened in Word 2010

    - by Candy
    If I have set styles in a Word 2003 document, how can I get the set styles to appear when the document is opened in Word 2010? When I open the document that was created using 2003 (that has set custom styles), in 2010 it converts everything to the 2010 styles. When I try selecting Change Styles?Style Set?Word 2003, it doesn’t pick up my custom styles; it only picks up the default 2003 styles. I want to be able to keep my custom styles that were created in the template using 2003.

    Read the article

  • Attempting to set up xampp and zend server on the same machine

    - by umbregachoong
    I am attempting to set up the zend server and xampp on the same machine but I am running into problems. I came across documentation on the zend site that said you cannot do this. However the folks over at apachefriends said you can. I have since discovered that I can run some of the zendframework examples within xampp by downloading the zendframework2 library and the skeleton app from git and I am doing this right now. However, I would like to know how to set them both up without having any conflicts both for the apache2 server and phpmyadmin. (One of the frustrating things is trying to load phpmyadmin in the deployment dialog by using the zpk tool in Zend). What I did in trying to set up both servers on windows 7 is as follows: First I have tried to set up the httpd conf files separately for each server, xampp running on port 8082 , and zend running on port 8088. At the time xampp would work, but zend server would not. This is after setting up the virtual host files separately for each server. Question 1: Where are the zend server error logs? Earlier, I was able to get both of them running configuring the xampp server httpd-conf file alone, however, I experienced problems with phpmyadmin even after configuring phpmyadmin on xampp to work on a different port other than 3306. Second question here: how to set up the two mysql phpmyadmin instances so they do not conflict with each other? Here is the xampp virtual host section: ##ServerAdmin [email protected] DocumentRoot "C:/xampp/htdocs/" ServerName localhost 8082 ##ServerAlias www.dummy-host.example.com ##ErrorLog "logs/dummy-host.example.com-error.log" ##CustomLog "logs/dummy-host.example.com-access.log" common Here is the zend virtual host section: DocumentRoot "C:\Program Files (x86)\Zend\Apache2/htdocs" ServerName localhost:8088 </VirtualHost> I have looked at this httpd.apache.org/docs/2.2/vhosts/ and this http://survivethedeepend.com/zendframeworkbook/en/1.0/creating.a.local.domain.using.apache.virtual.hosts but I am obviously doing something wrong here. I also have the java sdk running on this machine with tomcat and apache and I have no conflicts- too bad this is not the case for zend server and xampp Thanks umbre gachoong

    Read the article

  • changing timezone with dpkg-reconfigure tzdata and debconf-set-selections

    - by Carlos Campderrós
    I want to set up a script that automatically changes the timezone on a machine (running ubuntu 11.10) and also sets the right values to the debconf database. I've tried the following, but it does not work (at the end, the current timezone remains unchanged, and if I run manually the dpkg-reconfigure tzdata command, the selected values are indeed the old ones): #!/bin/sh -e echo "tzdata tzdata/Areas select Europe" | debconf-set-selections echo "tzdata tzdata/Zones/Europe select Madrid" | debconf-set-selections echo "tzdata tzdata/Zones/America select " | debconf-set-selections dpkg-reconfigure -f noninteractive tzdata So, by now, I'm doing it messing with the files /etc/localtime and /etc/timezone directly, but I'd rather prefer the dpkg-reconfigure and debconf way.

    Read the article

  • Set Folder Icon for all Os

    - by Am1rr3zA
    Hi, I want set icon to my folder in My external hard drive but when I change it (by right click on it and -> properties -> customize -> change icon (i address the icon from my extenal hard drive)) it just change in my windows and when plug my extenarnal-hard to another windows it's don't show my icon! how should fix this? P.S: is there a way to set icon for folder show in all os (linux, windows, OSX, ..) note: I don't want set icon to 1 drive I want set icon to all my folder in my drive.

    Read the article

  • set service dependency on internet connection

    - by nccsbim071
    Hi, I have created a window service and set some dependencies like on MSMQ, MSSQLSERVER and so. Everything is working nice. but i need to send another dependency for my service. That is on internet connection. My service is responsible for sending emails. As soon my server starts, my service starts too and it finds if there is anything to send, if there is, it starts to send email, if during sending it is not able to connect to the internet it cannot send email. so i guess i should set my service dependency on internet connection too. I already set my window service dependency to MicrosoftSQL Server and Microsoft Message Queuing by editing the registry value. by adding new multi string value named "DependOnService", Type "REG_MULTI_SZ" and space separated names of the services that my service depends upon for the Data. For Microsoft SQL Server i set the value to "MSSQLSERVER" but i don't know the name of the internet service that i need to set dependency upon. how can i do this, any help please Thanks

    Read the article

  • Set character_set_results UTF8 in MySQL my.cnf

    - by Marc
    Hi Folks, how can i set the Variable character_set_results from latin1 to uft8? I thought it would be enough if I would add the following variable in the my.cnf: default-character-set=utf8 But it not seem so: mysql SHOW VARIABLES LIKE 'character_set_%'; +--------------------------+----------------------------+ | Variable_name | Value | +--------------------------+----------------------------+ | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | utf8 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | utf8 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ Some body have an idea how i can set character_set_results to utf8?

    Read the article

  • Windows XP failing to set theme correctly on auto-login

    - by Alois Mahdal
    On several testing machines we have, when automatic login (as Administrator) is activated, Windows fails to set theme (Display properties - Themes) correctly. Particularly, even if theme is set to "Windows Classic", visually it's obvious that "Windows XP" is applied (the one with blue title bars and red "X" butons). I have only seen this happen when Auto-login is set--we always use Administrator on XP. Even if I log out and back in manually, theme is set correctly. Apart from logging out and in, it's also possible to reset theme in "Display properties". It does not happen in 100% of the cases, but it's way over 50%. Definitely it's often enough to be annoying. I believe this is a bug in Windows XP. I have never encountered it on other Windows versions. Does anybody know how to avoid this issue once forever? (Or can anybody provide explanation, relevant links, etc.?)

    Read the article

  • How to set original error message for apache 2.2

    - by ffffff
    Apache 2.2 default 414 message is Request-URI Too Large The requested URL's length exceeds the capacity limit for this server. I wanna set custom message so I set http.conf ErrorDocument 414 /error/HTTP_REQUEST_URI_TOO_LARGE.html.var But I do not get along well How to set original error message for apache 2.2

    Read the article

  • OSX Server - How to set environment variable on network user login

    - by tmkly3
    I have a group of users on my server, "Developers", and I would like an environment variable to be set for them whenever they login. More specifically, when anyone in this group logs in, I would like the equivalent of: setenv ANDROID_SDK_HOME /Developers/Android/User to be set at login. I can do this with a login script if necessary, but what I'm asking is: is it possible to set this type of thing in Profile Manager, Workgroup Manager, Directory Utility, etc? Thanks - I've looked everywhere but can't find anything.

    Read the article

  • How do you set up CRON?

    - by user1723760
    I have never used CRON before but I want to use CRON in order to be able to perform schedule jobs for a php script. The php script is called "inactivesession.php" and in the php script is this code: <?php include('connect.php'); $createDate = mktime(0,0,0,10,25,date("Y")); $selectedDate = date('d-m-Y', ($createDate)); $sql = "UPDATE Session SET Active = ? WHERE DATE_FORMAT(SessionDate,'%Y-%m-%d' ) <= ?"; $update = $mysqli->prepare($sql); $update->bind_param("is", 0, $selectedDate); $update->execute(); ?> Wht I want to do is that when the above date is reached (25th Oct), I want the php script to perform the UPDATE statement above. But my question is that how do I use CRON in order to do this? The server I am using is the university's server known as helios, does CRON need to be set up in helios, (do I have to call the admin for this) or is it something else which uses CRON. I have never used CRON before so can you explain to me how CRON can be set up for the example above with the server I am using? Thanks UPDATE: Hi, I think the name of the OS is actually helios but I am not sure, I have a wikipedia page on this: here. I will read the crontab wikipedia page and see what I can find, but what my question is that is CRON already set up, do I just go right ahead and use CRON or do I need to set it up first?

    Read the article

  • Where to set timeout value for website?

    - by gdavjenk
    I have a website that has its own application pool and uses ASP.net. The application interfaces with a SQL database. I changed the IIS timeout value from 20 minutes to 30 minutes but it still tinmes out at 20 minutes. If I set the IIS, ASP, and apppool timeouts all to 30 minutes it works correctly. Is there a single place I can set the timeout value or do I need to set the timeout in all three locations?

    Read the article

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >