User Tools

Site Tools


This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
creating_an_algorithm [2012/10/03 08:48]
creating_an_algorithm [2015/02/02 08:28] (current)
Line 1: Line 1:
 ====== Creating algorithms ====== ====== Creating algorithms ======
 ===== Including an algorithm in a page ===== ===== Including an algorithm in a page =====
-An algorithm is stored in a single page in the Algorithm namespace. Different variants ​require ​different pages. For +An algorithm is stored in a single page in the Algorithm namespace. Different variants ​of the same algorithm are stored on different pages. For 
 example Factorial recursive and Factorial iterative. example Factorial recursive and Factorial iterative.
Line 12: Line 12:
 ===== Creating an algorithm page ===== ===== Creating an algorithm page =====
-An algorithm page is split into three sections: +An algorithm page is split into five sections: ​Source, ​Support, Unit Tests, Options, and Visualisation. Each section is editable in a tabbed ​code editor at the bottom of the algorithm page.
-<​code>​ +
-====== Algorithm ====== +
-====== ​Support ​====== +
-====== ​Visualisation ​====== +
-Each of these sections contains code wrapped in %%<​syntax>​%% tags.+{{ :​editor-tabs.png?nolink |}}
 ==== Algorithm ==== ==== Algorithm ====
-The 1st section contains the algorithm. This is the code that the user sees in the interactive environment. +The 1st section contains the algorithm. This is the code that the user sees in the interactive environment. For example, this is the code for the Fisher-Yates shuffle algorithm
-<syntax js>+<code>
 function shuffle(a) { function shuffle(a) {
     for (var i=a.length-1;​ i>0; i--) {     for (var i=a.length-1;​ i>0; i--) {
Line 31: Line 26:
     return a;     return a;
 } }
 ==== Support ==== ==== Support ====
-The 2nd section contains the support code. This is support ​code, such as functions ​that the main algorithm ​uses. If it also includes a run() function this function is called when running the algorithm. +The 2nd section contains the support code. This is code that the main algorithm ​makes use of, for example utility functions. If the support code also includes a ''​run()'' ​function ​then this function is called when running the algorithm, instead of running the algorithm code from line 1
-<syntax js>+<code>
 function swap(a, i, j) { function swap(a, i, j) {
     var t = a[i]; a[i] = a[j]; a[j] = t;     var t = a[i]; a[i] = a[j]; a[j] = t;
Line 43: Line 38:
     return shuffle(a);     return shuffle(a);
 } }
 +==== Unit Tests ==== 
 +The unit tests section should contain unit tests to ensure the algorithm is correct. Each function in this section whose name has a '​test'​ prefix will be run on a web-worker thread. If there is any exception thrown during running the function the test fails. 
 +==== Options ==== 
 +The 4rd section contains options in JSON format. Available options are 
 +  * ''​title''​ -- The title algorithm. 
 +  * ''​height''​ -- The height of the transcluded algorithm. 
 +  * ''​preRunSource''​ -- If true, the algorithm source will be run at load time and the debugger buttons will initially be disabled. The debug controls enable when ''​runScript("​..."​)''​ is called from the visualisation. For an example of this in use see [[algorithm:​linked-list]]. 
 +  * ''​persistentGlobals''​ -- This is an array of strings referring to global variables. These are passed to web-workers each time ''​runScript''​ is called. 
 +  * ''​import''​ -- An array of strings of algorithm pages that will be imported as support code.  
 +A simple example is: 
 +    "​title":"​Fisher-Yates shuffle",​ 
 +    "​height":"​270px"​ 
 +For a more complex example see [[algorithm:​hash_set-open_hashing|λ Hash set open-hashing]].
 ==== Visualisation ==== ==== Visualisation ====
-The 3rd section contains the visualisation code. This is a complete ​webpage ​that contains ​an update() function, which is called ​for every new line when running the algorithm. The update function takes two arguments, the current node in the AST and an execution context. +The 4th section contains the visualisation code. This code is a self contained ​webpage, it is embedded in an iframe when displayed alongside the code. 
-<syntax html> + 
-<​html>​ +The webpage must provide a global ''​update()'' ​function, which is called ​at each new line when running the algorithm. The update function takes several ​arguments, ​ 
-  ​<​head>​ +  * ''​n'' ​the current node in the AST (This should be used very rarely) 
-    <script type="​text/​javascript">​ +  * ''​x''​ the execution context. 
-        ​function update(nx) { +  ​* ''​isRunning''​ is the debugger in the middle of running code? 
-            var element = document.getElementById("​container"​);​ +  * ''​duration''​ if the visualisation animateshow long it should takeIf ''​duration''​ is below 0 then visualising can be skipped if the update function is stateless
-            var i = x.lookupInScope("​i"​);​ +  * ''​prev''​ the prev continuation,​ if the visualisation is undo-able it should return a new prev continuation that calls this. 
-            var j = x.lookupInScope("​j"​)+ 
-            var a = x.lookupInScope("​a"​)+Two other functions are optional: ''​globals()''​ and ''​args()''​If the visualisation contains a global function ''​args()''​ then the return value of calling that function will be passed into the ''​run()''​ support functionThis allows the visualisation to supply the input to the algorithm. If ''​globals()''​ function is provided then it returns an object whose keys are added to the globals of the interpreter.
-            var xValue = x.lookupInScope("​x"​)+
-            if (i+
-               var arrayString = "​[";​ +
-               for (var k=0; k<a.length;k++) { +
-                   ​arrayString += i===k? "<​span style=\"​color:​red\">"​+a[k]+"</​span>"​ : j===k? "<​span style=\"​color:​blue\">"​+a[k]+"</​span>"​ : a[k]; +
-                   ​if ​(k < a.length-1arrayString += ", "; +
-               } +
-               ​arrayString += "​]";​ +
-               ​element.innerHTML = "a = " + arrayString + "<​br>"​+"​i = "+i; +
-           } +
-        } +
-    </​script>​ +
-  </​head>​ +
-  <​body>​ +
-  <pre id="​container"></​pre>​ +
-  </​body>​ +
-</​html>​ +
creating_an_algorithm.1349279299.txt.gz · Last modified: 2015/02/02 08:24 (external edit)