bug in LogFFE

[heikodietrich]

Hello!

I think I found a bug in LogFFE:

Observed behaviour

gap> F:=GF(269^2);;
gap> pr:=PrimitiveElement(F);;
gap> LogFFE(pr,pr);
1
gap> Order(pr) mod 3;
0
gap> pr := pr^(Order(pr)/3);;
gap> LogFFE(pr,pr);
fail   ### <----- BUG

Expected behaviour

gap> F:=GF(5^2);;
gap> pr:=PrimitiveElement(F);;
gap> LogFFE(pr,pr);
1
gap> Order(pr) mod 3;
0
gap> pr := pr^(Order(pr)/3);;
gap> LogFFE(pr,pr);
1

Copy and paste GAP banner (to tell us about your setup)

 ┌───────┐   GAP 4.11.0 of 29-Feb-2020
 │  GAP  │   https://www.gap-system.org
 └───────┘   Architecture: x86_64-apple-darwin19.6.0-default64-kv7
 Configuration:  gmp 6.2.0, GASMAN
 Loaded workspace: /Volumes/daten/gap-4.11.0/bin/ws.gap
 Packages:   AClib 1.3.2, Alnuth 3.1.2, AtlasRep 2.1.0, AutoDoc 2019.09.04, AutPGrp 1.10.2, CRISP 1.4.5, Cryst 4.1.23, CrystCat 1.1.9, CTblLib 1.2.2, FactInt 1.6.3,
             FGA 1.4.0, GAPDoc 1.6.3, IRREDSOL 1.4, LAGUNA 3.9.3, Polenta 1.3.9, Polycyclic 2.15.1, PrimGrp 3.4.0, RadiRoot 2.8, ResClasses 4.7.2, SmallGrp 1.4.1,
             Sophus 1.24, SpinSym 1.5.2, TomLib 1.2.9, TransGrp 2.0.5, utils 0.69
 Try '??help' for help. See also '?copyright', '?cite' and '?authors'
gap>

Thanks!
Heiko

[fingolfin]

This looks like a duplicate of issue #3784.

[heikodietrich]

Ups, sorry -- I didn't see that. But it's still happening :-)