nf = nfinit(x^5+x^4-4*x^3-3*x^2+3*x+1); t = nf.zk[2];
nfeltsign(nf, t)
nfeltsign(nf, t, 1)
nfeltsign(nf, t, [1..4])
nfeltsign(nf, [1,0,0,0,0]~, [1..4])
nfeltsign(nf, [-1/2,0,0,0,0]~, [1..4])
nfeltsign(nf, 0, 1)

nfeltsign(nf, x+950385237198502187979577282097391163977102921506573742575513/495253880608585631635195731645995689515566957889181807495428)
u = [x,2;2,-3];
nfeltsign(nf, u)
nfeltsign(nf, u, 1)
nfeltsign(nf, u, [1..4])

nf=nfinit(a^2-2);
for(n=1,100,if(nfeltsign(nf,Mod(a+1,a^2-2)^n)!=[(-1)^n,1],print(n)))

\\#2571
c=-114304969395075358172568956118107958797088205582487/8*x^2-1941762517087769652774338691007805097338043062848183/8*x+1316729173405932760915446743314396469951509506994957/2;
nf=nfinit(x^3+5*x^2+1240*x-2992); nfeltsign(nf,c)

\\#2217
pol=y^6-3*y^5+345*y^4-685*y^3-23547*y^2+23889*y-572438;
nf = nfinit(pol);
c=64113452896332165808752478841108920358611/18*y^4-64113452896332165808752478841108920358611/9*y^3-197187989995349756135115637139944886536280*y^2+3613497272812627776240833947360116878011651/18*y-46064974046127698515199898568801651913025508/9;
nfeltsign(nf,c)

\\ Errors
nfeltsign(nf, a, 3)
nfeltsign(nf, a, [-1..1])
nfeltsign(nf, a, [1..3])
