On Tue, Nov 8, 2011 at 12:22 PM, Jeroen Demeyer <jdeme...@cage.ugent.be> wrote: > On 2011-11-08 19:35, William Stein wrote: >> In this case, dirac_delta is actually a distribution. It >> is defined as the distribution with the property that >> >> integral(dirac_delta, a, b) >> >> is 0 if the interval [a,b] does not contain 0, and is 1 if the >> interval [a,b] does contain 0. > Not quite, even according to Sage: > > sage: integrate(dirac_delta(x), x, 0, 0) > 0 > For a and b different from 0, you are of course right but you cannot > really defining this integral from 0 to 0. > So, I think > numerical_integral(dirac_delta(x), x, 0, 0) isn't really defined.
OK, good points. It might be nice if there were a way to tell if a "symbolic function" is actually a distribution as opposed to an honest function, and then refuse to numerically integrate, or something. But that's for another day. -- William > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
