[Octave-bug-tracker] [bug #56489] System freeze due to Excel import

[Philip Nienhuis]

Update of bug #56489 (project octave):

                  Status:                    None => Need Info              

    _______________________________________________________

Follow-up Comment #1:

Maybe export the file (from excel) as a .csv file and read that. Have you
tried using the COM interface rather than OCT?

37 MB exploding to > 6.6 GB is weird. But OTOH to hold 6*170017 values a 37 MB
Excel file (and that is zipped size, FYI) is insanely big. The raw data would
occupy just 170017*5*8 bytes ~6.8 MB., so there would be 30 MB zipped (heaven
may know how much if unzipped) just for the spreadsheet overhead, and that is
quite out of proportion.
So, it may be that your .xlsx file contains e.g., loads of empty but formatted
cells that also have to be expanded into RAM before Octave can decipher
they're empty. So have you tried conveying an actual range (~ "A1:E170017")
rather than letting xlsread sort it out? Or can you try increasing that range
until you hit OOM errors?
A first try to see what the file looks like would be 
xlsfinfo ("rawdata.xlsx", "oct")
or
xlsfinfo ("rawdata.xlsx", "com")
and see how that goes.

FYI I sometimes read several years rather than 3 months of 10 min. values
(tidal data) and I don't see this problem.

Maybe you can upload the file somewhere or can I download it, than I can try
with later (dev) Octave versions.

    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?56489>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/