atilla

QUOTE(Aristos Queue @ Feb 14 2008, 06:23 PM)

A) Tomi isn't quite correct in his reply. A shift register does not always get a buffer allocation. It starts off with a buffer allocation, but we try to consolidate these down.

B) Your instincts are correct that we ought to be able to consolidate in this situation. EXCEPT... your inputs to the Initialize Array function are all constants. That means that Initialize Array has been constant folded and the buffer is there in your VI's save image. To avoid stepping on the value of the constant when we run the loop, the shift register makes its own copy. If you change any of those initial constants into controls, the buffer copy will go away.

Okay, that makes sense, thanks for the explanation Aristos!

atilla

QUOTE(george seifert @ Feb 14 2008, 05:15 PM)

Here's my code. There will be some subvis missing, but you don't need them to see what's going on with the shift register.

George

Download File:post-2786-1203005679.vi

Hello George,

Thanks for posting your code. I stripped it down and found something strange:

The first vi does not have the additional buffer. In the second I only changed the control to a constant, the buffer shows up... Looks like a bug?

atilla

QUOTE(george seifert @ Feb 14 2008, 02:45 PM)

That's odd. I'm doing something similar (2D array), initializing an array before the loop, sending it to a shift register and replacing array data within the loop. I'm not getting an allocation dot at the shift register. I'm using LV 8.5.

George

Hi George,

Odd indeed, this code is 8.5 as well. What does your code look like?

atilla

Hi all,

See the attached images.

The first vi with an array of doubles uses ~8 MB as expected. When I add a "Replace Array Subset" an additional buffer is created at the shift register, the used memory is doubled to 16 MB. Is there a way to avoid this? My intention is to replace existing array space, I don't see the need for an additional copy in this case ..

The In Place Structure doesn't work here either...

This is a cross post: http://forums.ni.com/ni/board/message?boar...=125662#M301485

Thanks in advance

atilla