Hi! On trac http://trac.sagemath.org/ticket/16813 Ralf Stephan and I come to the question which representation of legendre_Q and gen_legendre_Q is better suited, since it is not unique due to the complex logarithm. We have several choices to represent the logorithm appering in the formula of legendre_Q
1. log((1+z)/(1-z)) 2. log(1+z) - log(1-z) 3. conjugate(log((1+z)/(1-z)) It seems Maxima uses the first one, Wolfram the second one (indeed it has it's benefits). The third is possible but unhandy since you can't proper differentiate complex conjugation (except if you use Wirtinger operators of course, but not with the standard differential operator) The problem is now that version one and two are simply solutions on 2 different branches of the logarithm, therefore both correct but which one two choose. We think that V2 is better, but we have to make sure that it does not interfere with other code. The testing of sage is currently going on, but I wanted to ask on the mailing list if there are other reasons too, to stick on representation number 1. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
