Free implementations are liable. See Madey v. Duke University. It severely restricted the research exemption (http://en.wikipedia.org/wiki/Research_exemption ht

Free implementations are liable. See Madey v. Duke University. It severely restricted the research exemption (http://en.wikipedia.org/wiki/Research_exemption http://en.wikipedia.org/wiki/Research_exemption) I have had University Council tell me I cannot open source code I have written implementing patented algorithms. It is unfortunately more common than most people think, and often not acknowledged in publications.