[GAP Forum] Error in NormalSubgroups

[David Roe]

In my version of GAP (4.8.6 included in Sage, with the SmallGroups library
added), the following command produces an error:

gap> NormalSubgroups(SmallGroup(1458,1180));
Error, List Element: <list>[4] must have an assigned value in
  if map[d] > max  then
    elm := id;
else
    if not IsBound( map[d] )  then
        Error( "<elm> lies not in group defined by <pcgs>" );
    fi;
    ll := LeadingExponentOfPcElement( pa, elm );
    lr := lc[d];
    exp[map[d]] := ll / lr mod ros[d];
    elm := LeftQuotientPowerPcgsElement( pcgs, map[d], exp[map[d]], elm );
fi; at /home/roed/sage/local/gap/latest/lib/pcgsind.gi:1411 called from
ExponentsOfPcElement( NumeratorOfModuloPcgs( pcgs ), elm, pcgs!.depthMap )
at /home/roed/sage/local/gap/latest/lib/pcgsmodu.gi:931 called from
ExponentsOfPcElement( ocr.modulePcgs, x ) at
/home/roed/sage/local/gap/latest/lib/onecohom.gi:264 called from
ocr.moduleMap( n ) at /home/roed/sage/local/gap/latest/lib/onecohom.gi:339
called from
ocr.listToCocycle( lc ) at /home/roed/sage/local/gap/latest/lib/
grplatt.gi:1926 called from
opr( Zero( vs ), k ) at /home/roed/sage/local/gap/latest/lib/grplatt.gi:1932
called from
...  at line 1 of *stdin*

I tried installing the most recent version of GAP from source to see if the
error was also present there, but ran into a build error:

checking for GAP architecture... x86_64-apple-darwin16.7.0-gcc-default64

********************************************************************
  ERROR

  Found a GAP installation at /Users/roed/sage/gap4r8 but could not find
  information about GAP's architecture in the
  file /Users/roed/sage/gap4r8/sysinfo.gap or did not find the directory
  /Users/roed/sage/gap4r8/bin/x86_64-apple-darwin16.7.0-gcc-default64.
  This file and directory should be present: please check your
  GAP installation.
********************************************************************

configure: error: Unable to find plausible GAParch information.
= Failed to build xgap-4.26


Does anyone else see this error in finding the normal subgroups of
SmallGroup(1458, 1180)?  I'm able to successfully execute this command for
many other groups in the table of small groups....

Thanks,
David