Le mardi 20 août 2013 09:55:44 UTC+2, Antoon Pardon a écrit : > Op 20-08-13 09:31, wxjmfa...@gmail.com schreef: > > > Le mardi 20 août 2013 08:55:18 UTC+2, Antoon Pardon a écrit : > > >> > > >>> > > >> > > > > > >> > > >> > > >> > > >>> If you consider the implementation of sin and cos functions, they usually > > >> > > >>> reduce the argument modulo π to something in the first quadrant, and then > > >> > > >>> use symmetry to adjust the value. So changing the value of pi could, in > > >> > > >>> principle, change the implementation of sin, cos and tan. > > >> > > >> > > >> > > >> Yes there is this aspect, which is a fair point. > > >> > > >> > > >> > > >> -- > > >> > > >> Antoon Pardon > > > > > > ----- > > > > > > Not really, see my previous post. This is only a geometric > > > interpretation, useless for calculation. > > > > No it is not. Steven is correct that if for example you > > want the value of sin(10), that in a typical implementation > > this will be reduced to calculating -sin(10 - 3π). > > > > This for two reasons. It is faster to first reduce the argument > > within the first kwadrant, do the series expansion and then > > correct for sign than to expand the series with the original > > argument and it is more acurate because first reducing asures > > that all terms will stay relatively small while using the > > original arguments can intrduce some large terms that will > > have to cancel each other but that will reduce acuracy. > > > > -- > > Antoon Pardon
Ok. Fine. I was aware of the serie expansion, not about the reduction. jmf -- http://mail.python.org/mailman/listinfo/python-list
