Is it ok to use local variables within the same loop?

[BertMcMahan]

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@billko wrote:

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@David99999 wrote:

Would a channel writer/reader setup be better than a local variable for sharing data between loops?

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Probably over a billion times better, but I didn't check the math on that.

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I ran the numbers a while back and it's actually 1,000,000,000.33 (repeating, of course).

[thols]

@David99999 wrote:

Would a channel writer/reader setup be better than a local variable for sharing data between loops?

Channel wires were created to communicate between loops and they do it really well. Start here. I use them all the time for simple tasks like this and for much more complex message/actor-based architectures, and they always do their job, as well as make the code more readable.

[wiebe@CARYA]

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@David99999 wrote:

Would a channel writer/reader setup be better than a local variable for sharing data between loops?

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That depends on the channel wire type.

If you use a 'tag' channel wire (basically a current value), I don't think there's much difference regarding race conditions.

But once you start putting things in sub VIs (not possible with locals), at least you have a wire to track.

If you use a messenger or stream, the loops are synchronized, and you probably might as well use 1 loop.

[RTSLVU]

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wiebe@CARYA wrote:

If you use a messenger or stream, the loops are synchronized, and you probably might as well use 1 loop

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I don't believe this is true. 

What about a stream in a Producer/Consumer or SMH architecture?

[crossrulz]

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@RTSLVU wrote:

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wiebe@CARYA wrote:

If you use a messenger or stream, the loops are synchronized, and you probably might as well use 1 loop

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I don't believe this is true. 

What about a stream in a Producer/Consumer or SMH architecture?

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I think Wiebe went too generic in his comment.  From other conversations I have had with him, I'm pretty sure he was trying to refer to "Synchronous Communication" where loop 1 sends a command/request to loop 2 and then waits for a reply.  This is a form of synchronization that would make one think about if multiple loops is actually needed.

[wiebe@CARYA]

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@RTSLVU wrote:

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wiebe@CARYA wrote:

If you use a messenger or stream, the loops are synchronized, and you probably might as well use 1 loop

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I don't believe this is true. 

What about a stream in a Producer/Consumer or SMH architecture?

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In the context of the use case OP is picturing...

instead of a local, use a stream\messenger channel wire between two loops makes little sense (to me)...

[RTSLVU]

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wiebe@CARYA wrote:

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In the use case OP is picturing...

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Sure, but the OP's cases are not real world cases.

But they are common mistakes of using locals

[wiebe@CARYA]

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@RTSLVU wrote:

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wiebe@CARYA wrote:

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In the use case OP is picturing...

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Sure, but the OP's cases are not real world cases.

But they are common mistakes of using locals

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I concur...

[Magesh003]

Hi,

Local variable is not advisable to use inside the same loop. Instead you can use Functional Global variable. i have attached a reference of your code based on FGV. kindly refer that.

[thols]

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@Magesh003 wrote:

Hi,

Local variable is not advisable to use inside the same loop. Instead you can use Functional Global variable. i have attached a reference of your code based on FGV. kindly refer that.

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While an FGV would work here, it is completely unjustified. Just use the wire. Think dataflow!