ecpp_disc_cost, ecpp_disc_cost_v, ecpp_disc_cost_n

The estimated cost of realising a step with the discriminant d, in units of one scalar multiplication on the curve at a few thousand bits: the twists, the numerical computation of the class polynomials of the class field tower (cheap with Weber's function, which is usable for even D and, through the order of conductor 2, for odd D when the v of 4n = t^2 + |D| v^2 is even, as veven says), and the descent through the prime factors p of h (a square root for p = 2, radicals or a small powering for p = 3, a p-th root or a powering of a degree p polynomial otherwise), or the cost of a root of the genus field factor if that is smaller. ecpp_disc_cost_n uses n modulo 5, 7, 11 and 13 (nmodp, or the average over n if NULL) and scales the cost of the class polynomial numerics, which does not depend on n, to the bit size of n. ecpp_disc_cost is the optimistic estimate (with veven = 1) used to order and admit the pool. Class numbers with a prime factor above 13 get a cost above ECPP_DISC_COST_MAX.