Thank you. On Tuesday, May 26, 2015 at 5:29:09 PM UTC+3, Chris Smith wrote: > > When chop=True it uses the current precision to replace small arguments > with an exact zero. If you want to specify the threshold for chopping, pass > in a value instead of a boolean. The exp(-60) is about 8x10^-27 so if you > specify chop smaller than that you will not get 0 for the result: > > >>> expr.n(chop=1e-27) > 0.482830727370613 > >>> expr.n(chop=1e-26) > 0 > > > > On Thursday, May 21, 2015 at 1:49:34 PM UTC-5, Paul Royik wrote: >> >> OK. >> Thank you. >> Could you move it to issues? >> >> On Thursday, May 21, 2015 at 6:45:41 PM UTC+3, Aaron Meurer wrote: >>> >>> I'm guessing chop chops some intermediate expression that is smaller >>> than the cutoff in this case. It probably should be considered a bug. >>> >>> Aaron Meurer >>> >>> On Thu, May 21, 2015 at 8:53 AM, Paul Royik <[email protected]> >>> wrote: >>> > Nobody could tell how chop works? >>> > >>> > On Tuesday, May 5, 2015 at 11:41:24 AM UTC+3, Paul Royik wrote: >>> >> >>> >> expr = >>> >> >>> 2682469501914725726236807146020965585039500052171867725591732162347*exp(-60)/48648670709168952944186714683693506574127 >>> >>> >>> >> >>> >> N(expr) outputs 0.482830727370627 >>> >> but >>> >> N(expr, chop=True) outputs 0 >>> >> >>> >> In some other expressions chop doesn't make 0. >>> >> >>> >> So, how chop works? >>> > >>> > -- >>> > You received this message because you are subscribed to the Google >>> Groups >>> > "sympy" 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/sympy. >>> > To view this discussion on the web visit >>> > >>> https://groups.google.com/d/msgid/sympy/3ef42fe1-b3cb-45d3-80ef-6af88a181bb2%40googlegroups.com. >>> >>> >>> > >>> > For more options, visit https://groups.google.com/d/optout. >>> >>
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