matlab - changing the size of stencil during iterations within a for loop -


i have matrix [35rows x 39columns] of 2x1 column vectors, representing ordered pairs. have function creates 9 point stencil , evaluates points, returns 9 values , picks largest one. creates 9 point stencil centered largest return value located, , continues until function terminates @ global maximum value in matrix.

my question is, how can make stencil more efficient disregarding points has evaluated? don't want evaluate 9 points every time because take longer, , trying make process fast possible.

process: 1.) evaluate point , 8 surrounding it, 2.) pick largest of return values, 3.) move point, 4.) repeat

i referencing cell, use {i,j} indexing.

here's have code:

for k = 1:10^(6)              setpoint1 = field{i,j}(1);             setpoint1 = field{i,j}(2);              setpoint2 = field{i-1,j-1}(1);             setpoint2 = field{i-1,j-1}(2);              setpoint3 = field{i-1,j}(1);             setpoint3 = field{i-1,j}(2);              setpoint4 = field{i-1,j+1}(1);             setpoint4 = field{i-1,j+1}(2);              setpoint5 = field{i,j-1}(1);             setpoint5 = field{i,j-1}(2);              setpoint6 = field{i,j+1}(1);             setpoint6 = field{i,j+1}(2);              setpoint7 = field{i+1,j-1}(1);             setpoint7 = field{i+1,j-1}(2);              setpoint8 = field{i+1,j}(1);             setpoint8 = field{i+1,j}(2);              setpoint9 = field{i+1,j+1}(1);             setpoint9 = field{i+1,j+1}(2);

from there make 9 function calls, , record rsquared value (temp1 etc object multiple fields, concerned rsquared.)

            tempvec = [temp1.rsquared,temp2.rsquared,temp3.rsquared,temp4.rsquared,temp5.rsquared,temp6.rsquared,temp7.rsquared,temp8.rsquared,temp9.rsquared];             nextcenter = find(tempvec==max(tempvec));              if nextcenter == 1                 break;             end              if nextcenter == 2;                 = i-1;                 j = j-1;             elseif nextcenter == 3;                 = i-1;             elseif nextcenter == 4;                 = i-1;                 j = j+1;             elseif nextcenter == 5;                 j = j-1;             elseif nextcenter == 6;                 j = j+1;             elseif nextcenter == 7;                 = i+1;                 j = j-1;             elseif nextcenter == 8;                 = i+1;             elseif nextcenter == 9;                 = i+1;                 j = j+1;             end              nextcenter = [];      end

and dan, found out when comparing different algorithm :( can fix that, need stencil.

if there no more information available properties of function (monotonicity nice) there not better trying possibilities.

at least make sure once, guess trivial if go through of them.

if want performance, try cellfun little more complicated loop can give best speed.

if still looking way make heuristic more efficient, track progress:

tobeevaluated = true(35,39);

if consider evaluate point, check whether still done. after evaluating set value in progress matrix false.


Comments

Post a Comment

Popular posts from this blog

curl - PHP fsockopen help required -

i trying work on cloudflare api , have found in documentation. unfortunately have no idea how can use in fsockopen or through curl. here example of post request. need know how can make request below data post using curl or fsockopen curl https://www.cloudflare.com/api_json.html -d 'a=cache_lvl' \ -d 'tkn=8afbe6dea02407989af4dd4c97bb6e25' \ -d 'email=sample@example.com' \ -d 'z=example.com' \ -d 'v=agg' here link cloudflare https://www.cloudflare.com/docs/client-api.html#s4.2 try one: $ch = curl_init("https://www.cloudflare.com/api_json.html"); curl_setopt($ch, curlopt_returntransfer,1); curl_setopt($ch, curlopt_followlocation, 1); curl_setopt($ch, curlopt_ssl_verifypeer,false); // handling of -d curl parameter here. $param = array( 'a' => 'cache_lvl', 'tkn' => '8afbe6dea02407989af4dd4c97bb6e25', 'email' => 'sample@example.com', 'z' =...
Read more

HTTP/1.0 407 Proxy Authentication Required PHP -

i working in restricted network/limited access internet. since have use proxy make web service call. here php code calling web service , response . $client = new soapclient("http: //www.xyz.com/abc/wsdls/login.wsdl", array("trace" => 1, "exceptions" => 1, 'proxy_host' => $proxy_host, 'proxy_port' => $proxy_port, 'proxy_login' => $proxy_login, 'proxy_password' => $proxy_password)); response is fatal error: uncaught soapfault exception: [wsdl] soap-error: parsing wsdl: couldn't load ' http://www.xyz.com/abc/wsdls/login.wsdl ' : failed load external entity if copy url error message , paste in browser(with same proxy settings) works. 2nd scenario is, if pass values instead of variables giving me diffarant response $client = new soapclient("http: //www.xyz.com/abc/wsdls/login.wsdl", array("trace" => 1, "exceptions" => 1, 'proxy_host' ...
Read more

c# - Resource not found error -

i have problem accessing method on homecontroller. show code of method : [httpget] public actionresult decriptidentifiantetredirige(string login_crypter, string mdp_crypter) { string loginacrypter = _globalmanager.protegemotdepasse(login_crypter); string mdpacrypter = _globalmanager.protegemotdepasse(mdp_crypter); user userapp = new models.user(login_crypter, mdp_crypter); if (userapp.authentificationvalidee(userapp.userlogin, userapp.password)) { session["name"] = userapp.userlogin; return redirecttoaction("accueil", "home"); } else { return redirecttoaction("validerauthentification", "home"); } } then in routeconfig.cs wrote route : routes.maproute( name: "authentificationapresdecryptage", url: "{controller}/{action}/{login_crypter}/{mdp_crypter}", defaults: new...
Read more