Gary Rubin
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Posts posted by Gary Rubin
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QUOTE (Justin Goeres @ Jun 17 2008, 03:00 PM)
The servers were pretty swamped at first, but I managed to get through and get the download at about 10:30 AM US Pacific Time (30 minutes after scheduled launch).So far it seems significantly faster, and only a couple of my favorite Addons (e.g. Mouse Gestures) broke. I never used any of the betas or release candidates, so this is the first I've played with it.
Last night I couldn't get on the Mozilla site, but Download.com worked.
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QUOTE (crelf @ May 23 2008, 08:10 AM)
That said, I'd like to chime in on Chris's statement above.
Chris, I know you are a scientist by training, so I may be preaching to the choir.
I think you have to be careful about how you use the word "theory" in a scientific sense. In scientific terms, a theory has a higher burden of proof than what most people think of when they hear the word "theory". While I agree with you that theories are not certainties, I think that most non-scientists use the word "theory" to mean "hypothesis". According to the Scientific Method, a theory lies somewhere between a hypothesis and a law.
I like this representation of what a "theory" represents.
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I think Alfa has a kindred spirit in the Matlab world.
Here's a snippet:
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Dear Tim, write to direction. Exist a direction. You ask me to remove my files, but my files for me are jewels. If direction remove my files... ok... but i can't remove my work. I don't understand where is problem of my files? Programs are functional. Isn't possible to drink a coffee with my programs, but simulation is a function, and this function is a good function. In the software, line 804: (gravity1 + temperature1 ) / 2 = time1 = 3/2 * 0 with temperature1=0 and gravity1=2*0=00. Isn't illogical, not inside software. Also NaN, with your interpretation, is a philosophy. What is NaN? With a pc? But exist. NaN is an important component of Matlab. NaN=2? Why? In the software isn't illogical. Or, if is illogical... can i to understand motivation? If my theory is in error... can i to know where and because? All here. Bye -
QUOTE (BrokenArrow @ May 16 2008, 09:11 AM)
A company (who will remain nameless), has been in contact with me (more than once) to write some "drivers" for them, but in actuality, the job entailes working on the phone putting out fires for people who are struggling with interfacing LabVIEW to their products. They continually run a job ad that reads something like: provide customer solutions for (blah blah blah) must have excellent communication skills, Help Desk experience is desired, LabVIEW is a plus."I don't know whether it's amusing or sad that a company would think that LabVIEW experience is a "plus" but not a requirement for their in-house LabVIEW expert...
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QUOTE (rolfk @ May 16 2008, 02:54 AM)
Now I do write VI libraries too and develop "drivers" regularly. Some of them are openly available, some even free and I would hope that those libraries/drivers would not fall under your category of poorly written "LabVIEW SDKs". They definitly almost never use sequences and if they do it is for data dependency only and nothing else.
Rolf, I'm sure that nothing you release would be considered poorly written.
I'm refering to A/D board LabVIEW SDK's that I've seen that have used up to 14-frame stacked sequences nested within other stacked sequences and local variables to pass data from one sequence to the next.
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QUOTE (PaulG. @ May 15 2008, 10:00 AM)
LabVIEW SDK: ActiveX, dll's and/or C code drivers written by the manufacturer wrapped in LV Vi's. They usually include "example" programs demonstrating most of the functionality of the hardware along with full documentation*. They cost around $200 - $300.My experience is that these are usually so poorly written (i.e. overuse of sequence structures) that we end up rewriting them amost from scratch anyway. The Labview SDK's that I've used are often only useful as examples to show the order in which dll functions should be called and how their inputs need to be formatted.
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QUOTE (PaulG. @ May 13 2008, 02:12 PM)
The actual dll or C code is the "driver". Or am I full of pixie dust?I agree with that. If a VI is calling a device-specific DLL, I wouldn't call that VI a driver; the DLL would be the driver. I'd probably call a VI a driver if it was performing the hardware interface using only native Labview and OS functions (i.e. memory peeks/pokes).
Gary
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QUOTE (Michael_Aivaliotis @ Apr 1 2008, 04:20 PM)
I never use subroutine priority. I would like to see some benchmarking. Like many things in LabVIEW, such as thread priorities, the benefits of playing with them are highly overrated.Michael,
I know this doesn't qualify as a benchmark, but I have notes that using subroutine priority sped up one of my pretty large VIs by a factor of 10 (from ~13ms to ~1ms) as reported by LabVIEW's profiler. A caveats - I don't know how well the profiler reports on subroutine priority things.
This particular VI and its subvis have at least one 20k x 23-element matrix plus lots of 2k and 20k vectors running through and between them. I assume that the big performance boost had to do with subroutine priority handling memory allocation differently.
Gary
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QUOTE (Jim Kring @ Apr 1 2008, 03:53 PM)
Speaking of which - I remember Greg McKaskle from info-labview. Whatever happened to him. I assume he left NI?
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Oh, I also forgot to mention one of the limitations of subroutine priority - you can't use blocking processes in a subroutine subvi. If I remember correctly, that means no file I/O, queues, property nodes, etc.
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QUOTE (Jim Kring @ Apr 1 2008, 01:37 PM)
While I understand some of the basic principles of the subroutine setting, I'm not 100% certain about the best practices and rules of thumb for when to apply this setting and when to avoid it.Does anyone have any thoughts on this matter?
We have gotten good results using subroutine priority to speed up some fairly memory-intensive subvis. Our processing is inherently not very parallel, so we don't have to worry about the subroutine priority VI's stealing CPU time from each other. They inherit the thread from their caller, so if you want to do things in parallel, you might have to be careful about having too many subroutine subVI's called by the same caller.
Aristos, or someone else with more knowledge might correct me on this, but I think that our performance improvement may be due to the fact that our subroutine subVI's handle memory more effeciently due to the fact that they don't have to allocate anything for the front-panel controls and indicator.
Gary
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QUOTE (Chris Davis @ Mar 14 2008, 09:38 AM)
BTW, I've thought about volunteering to help kids learn about robotics and programming too. Perhaps something with First Lego League?That's a pretty cool organization. I was surprised that I wasn't able to find anything in my area (Northern Virginia). You'd think with all the tech business here, someone would be doing such things.
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Slightly off-topic, but...
My wife was an elementary-school teacher before resigning to stay home with our young kids. She is now working 2 afternoons a week at her old school doing an after-school reading program with a couple fourth-graders who need extra help. One of them has expressed an interest in robots and electronics, which got me thinking; if I had more free time, I think it would be fun and worthwhile to get an NXT kit and volunteer to spend time working with it with upper-elementary or middle=school kids. What better way to get kids interested in computers, programming, engineering, etc!
Anyone out there doing this?
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QUOTE(neB @ Mar 6 2008, 09:34 AM)
I don't have the strip but my favorite Dilbert is still...Frame 1
Dilbert walks into Radio Hut and is greated by a sales person who says "Hi, welcome to Radio Hut. I am half your age and know more about computers than you ever will, can I help you?"
Frame 2
Dilbert replies saying "Yes, I need a half dozen Niad pulse converters and an Anza-brush...."
Frame 3
Dilbert continues ".... or am I bluffing?"
Has any tried to buy a photo-diode or an SCR at Radio Shack lately?
Ben
I have a cousin who is a real computer nerd. He used to enjoy dressing up really scruffy, going to someplace like Best Buy, starting off asking very basic questions of the computer sales people, then asking them some really detailed technical question about system...
I didn't realize there was a Dilbert about him
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QUOTE(TiT @ Feb 7 2008, 03:28 AM)
When testing my image analysis functions I often use the conditionnal probe, why do they exist for DBL and not for SGL numerics ??Lots of IMAQ functions outputs values in SGL... I'm sure it wouldn't cost to develop !
Go to vi.lib/_probes.
Open the one you like (ConditionalDouble.vi, for example)
Edit it to change the data type to what you want, change the name and the Window Title.
Put it in user.lib/_probes
Voila! Single Conditional Probe!
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QUOTE(Gustavo Fernandes @ Jan 3 2008, 11:09 AM)
I was in hollidays.I wish everyone an happy new year 2008.
Gary, thank you very much for your reply.
I tried Mathscript but it is not what I'm looking for. I cannot copy paste my matlab code there. Too much work.
I'll try to call for NI help. I hope I can find a solution.
Gustavo,
Do you have this example?
C:\Program Files\National Instruments\LabVIEW 7.1\examples\scriptnode\Fractal.llb\MATLAB Script - Fractal.vi
Obviously yours won't be in a LabVIEW 7.1 directory, but the same example might be there in 8.5.
If so, open this and run it.
This is the structure that I'm talking about. I think you should be able to do anything here that you can do at the Matlab command prompt or in a script, including calling other functions. Try deleting the example matlab code and running 'bench', or calling your matlab code.
I really think this is what you're looking for.
I am able to paste Matlab code into that window and run it.
Gary
Rate of Change
in LabVIEW General
Posted
QUOTE (mross @ Jul 3 2008, 01:00 PM)
I may be missing something, but this approach only works for post-processing, doesn't it? If that's all you need to do, this can also be done with a lot less real estate using the Rotate Array function.