The Tor Browser / file revision

 // The Great Computer Language Shootout

 // http://shootout.alioth.debian.org/

 //

 // contributed by Ian Osgood

 function A(i,j) {

   return 1/((i+j)*(i+j+1)/2+i+1);

 }

 function Au(u,v) {

   for (var i=0; i<u.length; ++i) {

     var t = 0;

     for (var j=0; j<u.length; ++j)

       t += A(i,j) * u[j];

     v[i] = t;

   }

 }

 function Atu(u,v) {

   for (var i=0; i<u.length; ++i) {

     var t = 0;

     for (var j=0; j<u.length; ++j)

       t += A(j,i) * u[j];

     v[i] = t;

   }

 }

 function AtAu(u,v,w) {

   Au(u,w);

   Atu(w,v);

 }

 function spectralnorm(n) {

   var i, u=[], v=[], w=[], vv=0, vBv=0;

   for (i=0; i<n; ++i) {

     u[i] = 1; v[i] = w[i] = 0;

   }

   for (i=0; i<10; ++i) {

     AtAu(u,v,w);

     AtAu(v,u,w);

   }

   for (i=0; i<n; ++i) {

     vBv += u[i]*v[i];

     vv  += v[i]*v[i];

   }

   return Math.sqrt(vBv/vv);

 }

 var actual = '';

 for (var i = 6; i <= 48; i *= 2) {

   actual += spectralnorm(i) + ',';

 }

 assertEq(actual, "1.2657786149754053,1.2727355112619148,1.273989979775574,1.274190125290389,");