Pop Quiz, LabVIEW Experts

[alecjcook]

Hi LabVIEW experts.

   I have a question, and I'm going to pose it as a quiz.

I have 2 VIs, a main one and a sub on (see attached picture)

When I run the main VI, it calls the sub VI (which is essentially a functional global variable).

The question is. What is the value of the indicator "Array" after execution?

Cheers, Alec

[ShaunR]

Any 3 values between 1 and 9 in any order.?

[crelf]

With the load option as 0x48, that means your Sub.vi is going to have to be set for shared clone reentrant execution, so I'd say you'll get [3,6,9].

[drjdpowell]

Not sure how 0x8 and 0x40 options interact, but with 0x40 you are creating three shared clone pools, so the answer would be three values between 1 and 3, depending on how LabVIEW assigns idle clones in the pool.   With just 0x8, you’re making three clones, and the answer is [3,3,3].

[ShaunR]

Not sure how 0x8 and 0x40 options interact, but with 0x40 you are creating three shared clone pools, so the answer would be three values between 1 and 3, depending on how LabVIEW assigns idle clones in the pool.   With just 0x8, you’re making three clones, and the answer is [3,3,3].

 

I think it is one pool because of the strict type ref. Called in any order because of the Asych call and as if parallel iterations was enabled of the for loop..

For those who haven't seen this before. It is a demonstration of this behaviour. Foot Shooting factor 9000!

 

What do we get if we win? Can I go home early?

Edited January 6, 2016 by ShaunR

[Ryan Podsim]

3,6,9

Due to data dependency and loop iteration, the calls are sequential. Since the subVI must be a shared clone, only 1 clone is ever needed and thus 1 data space.

[alecjcook]

OK, so The answer is 3,6,9. Well done crelf and Ryan!

I would LIKE the answer to be "3,3,3". So the real question is... What do I have to do to this VI to achieve this?

 

 

With the load option as 0x48, that means your Sub.vi is going to have to be set for shared clone reentrant execution, so I'd say you'll get [3,6,9].

 

3,6,9

Due to data dependency and loop iteration, the calls are sequential. Since the subVI must be a shared clone, only 1 clone is ever needed and thus 1 data space.

 

Edited January 7, 2016 by alecjcook

[drjdpowell]

I would LIKE the answer to be "3,3,3". So the real question is... What do I have to do to this VI to achieve this?

Stop using the 0x40 pool option.   You don’t want a reference to pool of clones.  Try just 0x8.

[ShaunR]

OK, so The answer is 3,6,9.

Doh! It wasn't a call by asynch node that was used.

Opticians appointment confirmed.

 

Edited January 7, 2016 by ShaunR

[alecjcook]

Stop using the 0x40 pool option.   You don’t want a reference to pool of clones.  Try just 0x8.

nono, i DO want to reference a pool of clones.

I want to open 3 clones of the same VI, and be able to run them independently, and store the references so I know which clone instance i'm talking to

[drjdpowell]

nono, i DO want to reference a pool of clones.

I want to open 3 clones of the same VI, and be able to run them independently, and store the references so I know which clone instance i'm talking to

That’s not a “poolâ€.  That is three independent clones.  A pool is when you don’t care which instance you are talking to.

[ShaunR]

nono, i DO want to reference a pool of clones.

I want to open 3 clones of the same VI, and be able to run them independently, and store the references so I know which clone instance i'm talking to

 

Don;t wire anything to the "options" terminal of the open primitive.

 

You don't really want a shared pool, you want pool of 3 individual instances (pre-allocated).

[crelf]

So, how did you get on? Did you get what you were looking for?