https://bugs.documentfoundation.org/show_bug.cgi?id=129255
Bug ID: 129255
Summary: calc: wrong results, proposal to clear shared formula
./. autocalculate problems
Product: LibreOffice
Version: 4.2.0.4 release
Hardware: All
OS: All
Status: UNCONFIRMED
Severity: normal
Priority: medium
Component: Calc
Assignee: libreoffice-bugs@lists.freedesktop.org
Reporter: newbie...@gmx.de
Description:
sorry @all,
I have an unusual, and difficult, suggestion to get a handle on an annoying
problem.
Situation: since about five years (4.1 -> 4.2) LO calc suffers from errors in
the interaction between shared formulas and autocalculate.
Neither the developers nor the testers are able to think through the complexity
of relationships and dependencies that simple users can construct in sheets.
Users construct complex sheets, and are not able to completely control their
results.
Users are not aware that displayed results may be wrong.
Users need a reliable program, they need correct results.
Developers and Testers must (also) be able to dedicate themselves to other
tasks.
The processing of the complex 'shared formula ./. autocalculate' has brought
over several years only success messages for individual aspects being fixed,
the basic problem still remains.
See: https://bugs.documentfoundation.org/show_bug.cgi?id=111428#c21
I am not close enough to programming to decide whether the problem can be
solved with the current tools, my mathematical knowledge and my knowledge about
the structures in program and data are not enough to prove a theoretical
solvability.
I am close enough to 'testing' to think that it is largely impossible to prove
the correctness of all possible calculations by testing or to present them as
sufficiently 'probable'.
Imho that the malfunctions resulting from this bug-complex are serious and
undermine the trustworthiness of the program.
Hence the following suggestion:
A 'task-force' of developers and testers is formed to handle this problem with
priority.
The problem is approached from another side, it is started from the last
correct version and checked how complex it is to remove the special handling of
'shared formulae' from calc.
(Neutralizing the original implementation, working through and if necessary
neutralizing all patches based on it).
If enough manpower is available, two groups can work in opposite directions,
one as above and the second one goes 'backwards' through all patches that refer
to autocalculate and shared formulae and tries to show their correctness.
It may be that in this work the actual error is noticed and can be fixed.
If it is not found - hopefully - a version without 'shared formulas' will be
created that:
1) maybe works a little slower, but
2) provides correct results.
1. is probably to be overcome on the basis of the efficiency of current
hardware,
2. is important!
I think I'm talking about one to two man-years of development here, that's 'not
nice' :-(
... but the alternative to keep 'poking in the fog' and hope that by chance
you will find the real flaw among all the patches in the meantime is:
- uncertain in the result,
- Also expensive, so far certainly more than two man-years have been consumed
for this complex,
- also costly, after finding the error - at an uncertain point in time - all
patches installed afterwards - based on it - would have to be checked,
There might also be a third group trying to correct all the bugs found in the
first affected version, maybe you'll find a solution - the right one - quickly.
All in all, i would like to raise awareness of the problem and contribute to
the solution, rather than sticking to the role 'bad guy' - who still finds bugs
-
Steps to Reproduce:
See: https://bugs.documentfoundation.org/show_bug.cgi?id=111428#c21
it's only one flavour of this problem, you easily get plenty similar once you
raise the complexity in a sheet.
Actual Results:
cells unintentionally excluded form autocalculate,
Expected Results:
korrekt results in all cells
Reproducible: Sometimes
User Profile Reset: No
Additional Info:
Version: 6.5.0.0.alpha0+ (x64)
Build ID: 9ab43aebad67383057d2cc3f754ce2193fa78b4e
CPU threads: 8; OS: Windows 6.1 Service Pack 1 Build 7601; UI render: GL; VCL:
win;
Locale: de-DE (de_DE); UI-Language: en-US
Calc:
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