Date: prev next · Thread: first prev next last
2015 Archives by date, by thread · List index

At 12:14 12/02/2015 -0800, Spencer Graves wrote:
I recently noticed that a complicated spreadsheet that had previously functioned correctly was giving wrong answers without warning. After the usual wailing and gnashing of teeth, I traced the problem to a cell containing "=C4-SUM(G11:G1016)". Further experimentation produced the following simple version of the problem:

(1) Let A1=1, A2=2, and A3=sum(A1:A2); A3 computes here as 3.
(2) Insert cell A1 shift right.
(3) Observe: A3 now computes as 2. This is obvious in this case but far from obvious in a complicated spreadsheet, where the connection between A1 and A3 is obscure. In such cases, For an insert that would cause an error in a reference like A1:A2, I believe that Calc should issue a warning something like, "WARNING: Insert may change the answer computed in A3. Do you want to proceed?" I further think there should be no default and the user should be forced to select either "Yes" or "No".

Sorry, but I do not see how you can claim that the formula in A3 is "broken": it remains as =SUM(A1:A2) exactly as you entered it. What has changed is that you have displaced your data and made the result of the formula correctly different. I'm glad that Calc has allowed you to do this. If a spreadsheet program warned you when any calculated results might change, you would have to confirm just about every entry or change.

This was observed in LO, LO 4..5.0.0.alpha0 2015-02-05 00:36:56, and MS Excel 2003 sp3.

And perhaps in every other spreadsheet ever created?

Should this be filed as a bug report or a feature request?

Neither, I hope.

Wikipedia says, "A software bug is an error, flaw, failure, or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways." I think this fits that definition.

I don't see that the result is incorrect and I'm sure the behaviour is not unintended. I accept that you see this as an unexpected result, but then expectation is in the eye of the beholder.

A couple of points:

o Spreadsheets are useful only when the (usually hidden) formulae are appropriate and there is generally no way to ensure that this is so. Consequently spreadsheets are a fragile way to construct a means of computation. This is perhaps unfortunate but nevertheless true.

o One helpful technique might be, after selecting A1 and before creating the problem by displacing its value, to use Tools | Detective > | Trace Dependents to show where any dependent formulae are. This might help you to rethink your change.

I trust this helps.

Brian Barker

To unsubscribe e-mail to:
Posting guidelines + more:
List archive:
All messages sent to this list will be publicly archived and cannot be deleted


Privacy Policy | Impressum (Legal Info) | Copyright information: Unless otherwise specified, all text and images on this website are licensed under the Creative Commons Attribution-Share Alike 3.0 License. This does not include the source code of LibreOffice, which is licensed under the Mozilla Public License (MPLv2). "LibreOffice" and "The Document Foundation" are registered trademarks of their corresponding registered owners or are in actual use as trademarks in one or more countries. Their respective logos and icons are also subject to international copyright laws. Use thereof is explained in our trademark policy.