Gary Rubin

Hi gurus, I am trying to optimize a real-time data processing application. I believe that a big chunk of my time is associated with moving large arrays into and out of subvis, rather than actual calculation time. The nature of the processing does not lend itself well to parallelization, and 3rd-party driver considerations prevent us from using LVRT. Here's my question. Are there advantages (i.e. regarding inplaceness, etc.) to keeping vi's that share data in the same execution thread? Or conversely, are there penalties for spreading large memory blocks among various execution threads? Thanks, Gary

Hi all, I've never done much with Ethernet communication in my LabVIEW code, so this may be trivial... Here's what I'm looking to do: We have a system which is crunching numbers and generating results. This system has 3 ethernet ports. During normal operation, it will be using one of those ports to transmit data (via TCP/IP, I think) to a consumer of the data. I don't think there'll be an ethernet hub, at least not one that we'll have access to. What I've just described ought to be pretty straightforward. Here's where it gets tricky, at least in my mind: I'd also like to have the ability to walk up to the system with a laptop, plug a CAT-5 cable into one of the other ethernet ports, and start receiving the same transmitted data that's going over the TCP/IP. I was thinking of doing this one as UDP, however, so I don't have to worry about the system monitoring whether that laptop is connected or not. I guess my big question is whether port numbers are tied to the physical ports on the computer? In otherwords, do I need to assign my TCP/IP connection to Local Area Connection 1, and my UDP to Local Area Connection 2? Thanks, Gary Figured it out. Gary

QUOTE(torekp @ Jul 13 2007, 08:18 AM) Paul, Are you asking for the plain binary search, or my modified one with the interpolation at the end? EDIT: I've not been able to find my modified one, so here's the standard binary search. The modification was pretty simple - if the key is not found, lookup the array values associated with the upper and lower indices (upper will be smaller than lower), and interpolate between them.

Has alfa branched out to other languages? This showed up on the Matlab usenet. QUOTE

QUOTE(hooovahh @ Jul 2 2007, 09:10 AM) http://www.snopes.com/religion/pi.htm' target="_blank">Speaking of which...

QUOTE(yen @ Jun 26 2007, 03:35 PM) And I always pictured you as Japanese (i.e. '￥')

QUOTE(yen @ Jun 20 2007, 12:51 PM) My IE is 6.0.xxx

QUOTE(DDAdevil @ Jun 20 2007, 11:48 AM) I might not be understanding exactly what you're looking to do, but if you just want to monitor remotely, is Windows Remote Desktop or a similar 3rd party application a possibility?

There's an interview with NI's James Truchard in May 2007's RTC Magazine. http://www.rtcmagazine.com/home/article.php?id=100840

QUOTE(Michael_Aivaliotis @ Jun 20 2007, 03:42 AM) Works for me on IE and FF.

It would be nice if a wire or other BD object had a slightly different appearance to indicate whether there is a Description and/or Tip associated with it. Cross-posted from here, per Michael's suggestion.

QUOTE(orko @ Jun 19 2007, 03:48 PM) Thanks! I was looking for something other than #1, as it'd be a pain to mouse-over everything. Also, it doesn't seem to work on structures in 7.1.1. I see the context help for the structure, but it doesn't include my description like it does for other objects. Number 2 is an interesting trick. What exactly does that funky-looking string refer to? Thanks again, Gary

I was just thinking it would be nice if a wire or other BD object had a slightly different appearance to indicate whether there is a Description and/or Tip associated with it. Does LabVIEW 8.x do this? Thanks, Gary

My undergrad Computational Mechanics professor was into some of that "odd" stuff, especially synchronicity. Maybe one day I should read his book. I certainly have to credit him for getting me into the computational stuff I do now.

QUOTE(crelf @ Jun 14 2007, 05:02 AM) I'll second you on that one...

QUOTE(tcplomp @ Jun 13 2007, 08:28 AM) Is this what you want? http://msdn2.microsoft.com/en-us/library/bb267838.aspx''>http://msdn2.microsoft.com/en-us/library/bb267838.aspx' target="_blank">http://msdn2.microsoft.com/en-us/library/bb267838.aspx

QUOTE(eaolson @ Jun 5 2007, 04:48 PM) That sounds familiar. Does it have other examples of operations inside and outside loops?

QUOTE(eaolson @ Jun 5 2007, 11:18 AM) I'm glad that you seem to have the same recollection that I do. I'm away from my office right now, but I'll have to look hard for that document when I get back.

QUOTE(Aristos Queue @ Jun 4 2007, 02:23 PM) Yes, when I do that they run at the same speed, which was what got me confused again about why I thought I remembered reading that there's a performance difference between operations inside loops vs. operating on arrays. I'm beginning to think that I must have missed a distinction between always avoiding operations inside loops vs. avoiding operations inside loops that result in extra memory allocations. Either that or I'm thinking back to LV5-era guidelines that no longer apply.

QUOTE(Omar Mussa @ Jun 4 2007, 10:37 AM) You are correct. I need to stop trying to think on Monday mornings. It just isn't working out well... That means my previous question still applies. Am I just imagining a past App Note that recommended operating on arrays rather than on each element inside a for loop?

QUOTE(tcplomp @ Jun 4 2007, 09:05 AM) Very good point. If I replace the constant with a the Random Number primitive, the array implementation is 25 times faster than the loop implementation.

QUOTE(Aristos Queue @ May 31 2007, 10:26 AM) Based on this comment, I did a little playing around in LV7.1.1 with some simple operations both inside and outside loops, i.e. this: http://forums.lavag.org/index.php?act=attach&type=post&id=6016 vs. this: http://forums.lavag.org/index.php?act=attach&type=post&id=6015 I was really surprised to find out that they take the same amount of time. I can't find it anywhere, but didn't there used to be an App Note that said that the first way is more efficient than the second? Gary

QUOTE(Mike Ashe @ May 31 2007, 09:42 AM) I see. Thanks. I was thinking you were passing data between Labview Embedded and Matlab.

QUOTE(Mike Ashe @ May 31 2007, 09:23 AM) Mike, I understand that your NDA may prevent you from saying much, but can you talk about the nature of how you tied Labview Embedded and Matlab together? Gary

I've been working with Matlab recently and have been really impressed with some of its array indexing capabilities, in particular the ability to use an vector as the index argument and a boolean array for indexing. For example, it would be nice to be able to do the following in Labview LabVIEW: http://forums.lavag.org/index.php?act=attach&type=post&id=5989 Given LabVIEW's polymorphic operators (i.e. same operator for scalar, vector, matrix, etc. inputs), I would naively think this would be feasible. I could clearly write subvis to replicate this behavior but I don't see any way to do it without some sort of looping, which would be slower than a native capability.