Rational points on elliptic curves over the rationals ellrank The GP function ellrank attempts to compute the rank of the the Mordell-Weil group attached to a curve. This is based on Denis Simon’s GP script for 2-descent. The function returns [r, R, L] such that the rank is between r and R (both included) and L is a list of independent, non-torsion rational points on the curve. ? E = ellinit([-289,1]); ? ellrank(E) %2 = [5,5,[[-3,29],[-7,41],[-1,17],[-15,31] % ,[-16,23]]] Favorable case: the rank is 5 and a Q-basis is known.