Hard to say without knowing more about your implementation, but even with SIQS the number of duplicates is not expected to be large. I would suspect a bug, or at least inadvertent selection of the same polynomials multiple times. The other possibility is that your factor base is too small, so that if you only allow one large prime above the factor base bound then that large prime occurs often, in many relations.
Last fiddled with by jasonp on 20080814 at 12:36
