initial commit

README.md

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 rle-stencils
 ============
 
-Stencil generator code for the rle libraries
+Stencil generator code for the rle libraries
+
+
+Basic Usage
+===========
+
+To install the library, just do:
+
+    npm install rle-stencils
+
+Then in your code you can import the stencils by:
+
+    //Import stencil library
+    var stencils = require('rle-stencils');
+
+Example: Moore
+--------------
+
+Here is how to create a stencil for a [Moore neighborhood](http://en.wikipedia.org/wiki/Moore_neighborhood) with radius 2:
+
+    var moore_neighborhood = stencils.moore(2);
+
+Example: von Neumann
+--------------------
+
+And here is the same idea applied to a [von Neumann neighborhood](http://en.wikipedia.org/wiki/Von_Neumann_neighborhood)
+
+    var von_eumann_neighborhood = stencils.vonNeumann(1);
+
+Example: Sphere
+---------------
+
+    var ball_neighborhood = stencils.ball(5);
+
+Example: L^p
+------------
+
+More generally, you can create a stencil for any [Lp ball](http://en.wikipedia.org/wiki/Lp_space), with p being some fixed power.  For example, here is how to make an L^3 ball with radius 6:
+
+    var cubic_neighborhood = stencils.lp(3, 6);
+
+In general, calls to `lp(p, r)` return the collection of all integer lattice points `x` satisfying the inequality:
+
+    Math.pow(Math.abs(x[0]), p) + Math.pow(Math.abs(x[1]), p) + Math.pow(Math.abs(x[2]), p) <= Math.pow(r, p)
+
+Acknowledgements
+================
+(c) 2013 Mikola Lysenko.  MIT License

package.json

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+{
+  "name": "rle-stencils",
+  "version": "0.0.0",
+  "description": "Stencils for use with rle library",
+  "main": "stencils.js",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/mikolalysenko/rle-stencils.git"
+  },
+  "keywords": [
+    "stencil",
+    "narrowband",
+    "levelset"
+  ],
+  "author": "Mikola Lysenko",
+  "license": "MIT",
+  "readmeFilename": "README.md",
+  "gitHead": "41b5fa5b369a8894a6196fdea2efce0e94daead5"
+}

stencils.js

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+//Generates a Moore neighborhood with given radius
+function moore(radius_) {
+  var result = []
+    , radius = Math.ceil(radius_);
+  for(var i=-radius; i<=radius; ++i) {
+    for(var j=-radius; j<=radius; ++j) {
+      for(var k=-radius; k<=radius; ++k) {
+        result.push([i,j,k]);
+      }
+    }
+  }
+  return result;
+}
+
+//Creates an Lp ball stencil
+function lp(p, radius_) {
+  if(p === Number.POSITIVE_INFINITY) {
+    return moore(radius_);
+  }
+  var result = []
+    , radius = Math.ceil(radius_)
+    , rp     = Math.pow(radius_, p);
+  for(var i=-radius; i<=radius; ++i) {
+    for(var j=-radius; j<=radius; ++j) {
+      for(var k=-radius; k<=radius; ++k) {
+        if(Math.pow(Math.abs(i), p) + Math.pow(Math.abs(i), p) + Math.pow(Math.abs(i), p) <= rp) {
+          result.push([i,j,k]);
+        }
+      }
+    }
+  }
+  return result;
+}
+
+exports.lp         = lp;
+exports.moore      = moore;
+exports.vonNeumann = lp.bind(this, 1);
+exports.ball       = lp.bind(this, 2);