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simplify_rational() takes very long or forever for some complex exponential expressions #16724

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sagetrac-gansmann mannequin opened this issue Jul 28, 2014 · 3 comments

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@sagetrac-gansmann
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sagetrac-gansmann mannequin commented Jul 28, 2014

For some sums of exponential functions with complex arguments, simplify_rational() takes very long or is caught in an infinite loop (it did not finish in 40 minutes).

 (e^(8/5*I*pi) + e^(4/5*I*pi)).simplify_rational()

Component: symbolics

Keywords: simplify symbolics exponentials

Issue created by migration from https://trac.sagemath.org/ticket/16724

@sagetrac-gansmann sagetrac-gansmann mannequin added this to the sage-6.3 milestone Jul 28, 2014
@sagetrac-vbraun-spam sagetrac-vbraun-spam mannequin modified the milestones: sage-6.3, sage-6.4 Aug 10, 2014
@rwst
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rwst commented Aug 29, 2016

comment:2

This is no longer the case because Pynac automatically expands many trigonometric expressions with rational multiples of pi, before the expression is handed to Maxima.

sage: e^(8/5*I*pi) + e^(4/5*I*pi)
-1/4*I*sqrt(2*sqrt(5) + 10) + 1/4*I*sqrt(-2*sqrt(5) + 10) - 1/2

@rwst rwst removed this from the sage-6.4 milestone Aug 29, 2016
@bgrenet
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bgrenet commented Aug 29, 2016

comment:3

Tested here too.

@embray
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embray commented Aug 30, 2016

comment:4

Determined to be invalid/duplicate/wontfix (closing as "wontfix" as a catch-all resolution).

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