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fixed ImaginaryPart for quaternion algebras #2938

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merged 1 commit into from
Oct 24, 2018
Merged

fixed ImaginaryPart for quaternion algebras #2938

merged 1 commit into from
Oct 24, 2018

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ThomasBreuer
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@ThomasBreuer ThomasBreuer commented Oct 23, 2018 •
edited by fingolfin
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Fixes #2801.

stevelinton
stevelinton approved these changes Oct 23, 2018
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Looks correct.

fingolfin
fingolfin approved these changes Oct 24, 2018
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Seems to fix the issue, thanks!

tst/testinstall/algsc.tst
gap> List( gens, RealPart );
[ e, 0*e, 0*e, 0*e ]
gap> List( gens, ImaginaryPart ) * gens[2];
[ 0*e, i, j, k ]
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A slightly more extensive test could test the identity claimed by the manual; based on #2801:

...
gap> vecs := Concatenation( gens, [ Sum( gens ) ] );
[ e, i, j, k, e+i+j+k ]
gap> ForAll( vecs, v -> (v + ComplexConjugate( v )) / 2 = RealPart(v) );
true
gap> ForAll( vecs, v -> (v - ComplexConjugate( v )) / (2*gens[2]) = ImaginaryPart(v) );
true

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O.k., I have extended the test.

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codecov bot commented Oct 24, 2018

Codecov Report

Merging #2938 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2938      +/-   ##
==========================================
+ Coverage    83.8%    83.8%   +<.01%     
==========================================
  Files         681      681              
  Lines      346794   346748      -46     
==========================================
- Hits       290627   290595      -32     
+ Misses      56167    56153      -14
Impacted Files Coverage Δ
lib/algsc.gi 91.47% <100%> (+0.46%) ⬆️
src/calls.h 95.74% <0%> (-2.2%) ⬇️
hpcgap/lib/hpc/stdtasks.g 71.77% <0%> (-0.41%) ⬇️
lib/read5.g 100% <0%> (ø) ⬆️
src/intrprtr.c 98.83% <0%> (ø) ⬆️
src/c_oper1.c 93.55% <0%> (ø) ⬆️
src/funcs.c 97.74% <0%> (ø) ⬆️
src/listfunc.c 94.3% <0%> (+0.01%) ⬆️
src/listoper.c 80.12% <0%> (+0.02%) ⬆️
src/gvars.c 82.6% <0%> (+0.03%) ⬆️
... and 6 more

@ThomasBreuer ThomasBreuer merged commit 26b88ca into gap-system:master Oct 24, 2018
@ThomasBreuer ThomasBreuer deleted the TB_RealPart branch October 24, 2018 14:51
@PaulaHaehndel PaulaHaehndel added kind: bug Issues describing general bugs, and PRs fixing them release notes: to be added PRs introducing changes that should be (but have not yet been) mentioned in the release notes labels Apr 15, 2019
@wucas wucas added kind: bug: wrong result Issues describing bugs that result in mathematically or otherwise wrong results, and PRs fixing them release notes: added PRs introducing changes that have since been mentioned in the release notes and removed release notes: to be added PRs introducing changes that should be (but have not yet been) mentioned in the release notes labels Aug 20, 2019
@olexandr-konovalov olexandr-konovalov added this to the GAP 4.11.0 milestone Feb 15, 2020
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@stevelinton stevelinton stevelinton approved these changes

@fingolfin fingolfin fingolfin approved these changes

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kind: bug: wrong result Issues describing bugs that result in mathematically or otherwise wrong results, and PRs fixing them kind: bug Issues describing general bugs, and PRs fixing them release notes: added PRs introducing changes that have since been mentioned in the release notes
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Successfully merging this pull request may close these issues.

Definition of ImaginaryPart for quaternion algebras unclear
6 participants
@ThomasBreuer @fingolfin @stevelinton @olexandr-konovalov @wucas @PaulaHaehndel