// 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,");