def math = use('math/radians'); function A(i,j) { return 1/((i+j)*(i+j+1)/2+i+1); } function Au(u,v) { var i = 0 var j = 0 var t = null for (i = 0; i < length(u); ++i) { t = 0; for (j = 0; j < length(u); ++j) t += A(i,j) * u[j]; v[i] = t; } } function Atu(u,v) { var i = 0 var j = 0 var t = null for (i = 0; i < length(u); ++i) { t = 0; for (j = 0; j < length(u); ++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 = 0 var u = [] var v = [] var w = [] var vv = 0 var vBv = 0 for (i = 0; i < n; ++i) { u[i] = 1; v[i] = 0; 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); } log.console(spectralnorm(arg[0]).toFixed(9)); $stop()