[Octave-bug-tracker] [bug #51512] [octave forge] (io) Missing or wrong types when using xlsread with OCT interface

[Philip Nienhuis]

Follow-up Comment #25, bug #51512 (project octave):

I had a try with __OCT_xls2oct__.m where I split up the regexp for numeric
data into 6 different regexps (see attached).
Results:

Separate regexps:

>> tic; [~,~,raw] = xlsread ('test.xlsx', 1, '', 'oct'); toc
separate regexps
Elapsed time is 127.262 seconds.


and with the "original" combined regexp:

>> tic; [~,~,raw] = xlsread ('test.xlsx', 1, '', 'oct'); toc
separate regexps
Elapsed time is 84.8379 seconds.


My conclusion here:
As to speed, one combined regexp to catch all XML syntaxes is better than
separate regexps for each specific XML syntax.
But it may be that splitting up the XML txt string may be better to avoid OOM
issues. But as I haven't hit those (even with big spreadsheets filling up RAM
usage by Octave to > 7 GB) for the time being I'll ignore this risk.


As to stanza #3 in your comment #23, I think I'll stick to the combined regexp
and not implement distinct groups, sacrificing some speed if a user wants
formula output. 
One reason is that AFAICS several distinct regexps would needed for each
"class" of formula result (double, text or boolean) to be able to avoid
reading those values as you suggest. But maybe I'm wrong?

Hopefully this weekend I'll commit a patch for one of my __OCT_xlsx2oct__ .m
versions in comment #18 or (peferrably) your amended version in comment #19 so
that this bug can (finally) be closed.
Do you still have the latter version? was that file #41505 ?

Subsequently I hope to be able to make a new io release soon after.


(file #42122)
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Additional Item Attachment:

File name: __OCT_xlsx2oct__.m             Size:10 KB


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