id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
28207,Derivative of piecewise function returns junk,rburing,,"Reported in [https://ask.sagemath.org/question/47169/plotting-derivative-of-bump-function/ Ask SageMath question #47169], we can't differentiate the bump function:
{{{
sage: f(x) = piecewise([((-oo, -1), 0), ((-1, 1), exp(-1/(1 - x^2))), ((1, oo), 0)])
sage: f.diff()
x |--> (0, 0, 0)*D[0]piecewise(x|-->0 on (-oo, -1), x|-->e^(1/(x^2 - 1)) on (-1, 1), x|-->0 on (1, +oo); x) + D[1]piecewise(x|-->0 on (-oo, -1), x|-->e^(1/(x^2 - 1)) on (-1, 1), x|-->0 on (1, +oo); x)
sage: f.diff()(0)
(0, 0, 0)*e^(-1) + e^(-1)
sage: f.diff()(0) in RR
False
}}}
That's not right...",defect,closed,major,sage-9.5,symbolics,fixed,"piecewise,derivative,diff",tscrim slelievre gh-kliem,,Frédéric Chapoton,Travis Scrimshaw,N/A,,2f0c8282bee61453e962f57cdc2a16be746ba097,2f0c8282bee61453e962f57cdc2a16be746ba097,,