Re: Limit in waveform data size?

2004-05-08 Thread chutla
Dear Carnivorus:

 I would venture to say that perhaps there is not enough memory to
 complete the operation! :)   All snide aside, working with large
 arrays takes some serious number crunching.  You might try twiddling
 your swap file size (on the Advanced properties tab of My Computer in
 win2K and later).  However, you're probably bumping up against the
 absolute limit of the OS.
 If there is ANY way of dividing and conquering your data so as to
 not have to deal with such a large array, I think you should
 invistigate it.  YOu may find you don't need anywhere near the samples
 you think you do.  (voice of experience,here!)  Or perhaps you don't
 need the dynamic range.  (On most DAQ cards, you can't change the
 number of bits, but you might be able to use a card with fewer than
 you're currently using)

   Eric



Limit in waveform data size?

2004-05-07 Thread Carnivorus
Here is the situation:
I have to process files which contains records.
These records contain data of the waveform datatype.
I need to append the record to eachother, using a (while)loop,
appending the Y values only as the rest of the attributes and values
are the same.

The problem:
If i try to process large files like say 670Mb the appending works for
a while but stops at some point with the remark Not enough memory to
complete operation
The icon is flashing where i append the Y array starts blinking (the
append array icon form tha array tool pallet).
Files with a size up to 200Mb do not generate this error, i do not
have any files with a size in between.

I also tried to reserve space up front based on the number of records.
I used the 'intialise array' for this but it also failed with the same
remark


Question:
- Is there a limit in the amount of data that can be but into wavevorm
data type instance
- Is there a limit in the append function
- Am i getting stuck on limitations on memory in Labview or windows

I use a P4 machine with 1Gb of physical RAM



Re: Limit in waveform data size?

2004-05-07 Thread Greg McKaskle
 Question:
 - Is there a limit in the amount of data that can be but into wavevorm
 data type instance
 - Is there a limit in the append function
 - Am i getting stuck on limitations on memory in Labview or windows
 

You probably want to use the task manager or other Windows tools to see 
just how much memory is being used.  My guess is that you get the 
message when the process hits 2G of virtual memory, and that is the 
limit imposed by the OS.  Keep in mind that when you are manipulating 
large arrays that copies can be made, and to display them copies must be 
made.  These can be minimized to a point, but at some point the 
convenience of dealing with a simple arrays takes too much memory and 
you need to operate in blocks or on decimated data.  There are some 
pretty good articles on dealing with large arrays on the NI web site.

Greg McKaskle