Hi,
While doing some stress-testing on the java-based spreadsheet <-> octave
scripts I consistently run into Java problems on the Windows platform
(using the octave-3.2.3-MingW binary + java package 1.2.6 sent to me a
while ago by Michael Goffioul - i.e. the same as in svn).
I haven't encountered these problems on Linux.
AFAICT it starts with heap space problems when accessing spreadsheets
with relatively big data arrays (size order of 10^5 elements; IMO big
but not extremely big).
Later on when trying to read or write much smaller chunks I get other
errors, but I suspect these are related to fubarred java structures in
memory as a byproduct of the java heap wrecked earlier on.
That suspicion is more or less confirmed by restarting octave -
reading/writing spreadsheets (ods or xls) is OK then until another too
big chunk is to be written using one of the java interfaces.
An example is below:
octave-3.2.3.exe: #1 > xls = xlsopen ('bigfile.xlsx', 1, 'poi');
Java/Apache POI interface requested... Java/Apache (POI) OK. (& OOXML OK)
Creating file bigfile.xlsx
octave-3.2.3.exe: #2 > ggg = rand (300, 1024);
octave-3.2.3.exe: #3 > xls = oct2xls (ggg, xls, 'BigArray','A1:AMJ500')
error: [java] java.lang.OutOfMemoryError: Java heap space
error: called from:
error: c:\home\philip\mydocs\octave\oct2xls.m at line 468, column 10
error: c:\home\philip\mydocs\octave\oct2xls.m at line 90, column 17
octave-3.2.3.exe: #3 >
Similar errors occur when reading from/writing to .ods /.xls
spreadsheets no matter what java interface I use (ApachePOI, JExcelAPI,
ODFtoolkit, jOpenDocument).
So apparently there is a memory usage limit for the java package on
Windows systems.
AFAICS transferring data structures (numerical or cell arrays) of up to
about 80,000 elements seems to be OK.
On Linux I've transferred much larger arrays to and from xls, xlsx and
ods spreadsheets with the same scripts and java jars (sizes of up to
1,000 x 1,024) without a hitch. This made me conclude that it must be
the java-package that has issues on the Windows platform.
I tried to run the same scripts using the deprecated MSVC 3.0.3 octave
binary that I still have installed, but it turned out that version (with
java-1.2.5) was even more fragile: I got java errors with much
smaller blocks.
Being not very proficient in java or C++ programming, what can I do help
fix this issue?
Philip
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