[Octave-bug-tracker] [bug #53005] Variable editor: slow performance with large arrays

[Dan Sebald]

Follow-up Comment #8, bug #53005 (project octave):

I've done some testing in LibreOffice Calc to see what happens with a 1000 x
1000 matrix in a spreadsheet.  You can try this as well.  Attached are some
screenshots.

Filling_1000_x_1000_Cells_With_Random_Screenshot_from_2018-01-30_22-07-33.png
Go to Sheet::Fill Cells::Random Number... and enter a range of $A$1:$ALL$1
then OK.

Select_And_Autofit_1000_x_1000_Cells_Screenshot_from_2018-01-30_22-10-49.png
In that small Navigotor dialog box, click on the top-left Data Range icon. 
Note that at the bottom of the LibreOffice Calc window is a "1000 rows, 1000
columns selected".  Now go to Format::Autoformat Styles... window and unselect
all the options except for "AutoFit width and height".  Select OK, then
mouse-click in a cell somewhere, move the mouse wheel up and down a bit...the
wait.

Autofit_Result_Screenshot_from_2018-01-30_22-16-35.png
This is an example of the result I see where there are a few columns autofit
wide compared to most columns.

OK, as for time, where I noted above that one should wait after selecting
AutoFit, I'm seeing a delay of 18 seconds, yes 18.  In Octave's Variable
Editor (V.E.) it seems to be a 1/2 or 1/3 fraction of that time probably
because L.O. Calc is doing both columns and rows.  Octave V.E. does only
columns.

In summary, I don't think there is anything good/bad about Octave's
implementation of this Autofit feature, it's just the nature of the
spreadsheet-like problem with so much data to loop through.  Given that, I
think the answer here is to not have the Autofit feature as an automatic
thing, configured in "Preferences".  Instead, take that out of Preferences and
instead add the Autofit to the V.E. in some way as a one-time selection by the
user.  How?  I don't know.  Some radio button in the header?  Some
right-mouse-click-and-drop-down-menu selection?

(file #43129, file #43130)
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Additional Item Attachment:

File name:
Filling_1000_x_1000_Cells_With_Random_Screenshot_from_2018-01-30_22-07-33.png
Size:99 KB
File name:
Select_And_Autofit_1000_x_1000_Cells_Screenshot_from_2018-01-30_22-10-49.png
Size:207 KB


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