[Swift-user] Re: [Swift-devel] Problem with iterate

[Ioan Raicu]

Sent again from my UChicago adress:

Ioan Raicu wrote:
> But lets bring this back to a more real example. A user wanting to 
> express some computations that have some dependencies, would write out 
> their computations in some order, expecting their order to be 
> preserved because of the dependencies. If you only support single 
> assignment on variables (e.g. the data), then an example like the one 
> below could never deadlock because the single assignment would be 
> violated on the 2nd statement. Perhaps things are more complicated if 
> you support multiple assignments per variables, but that is not the 
> case for Swift, right?
>
> I am trying to understand if this deadlock is happening in Swift due 
> to some particular implementation detail in Swift (or underlying 
> pieces), or is it a fundamental flaw in the DAG based approach with 
> single assignment variables? Or is it due to something completely 
> different?
>
> Thanks,
> Ioan
> -- 
> =================================================================
> Ioan Raicu, Ph.D.
> NSF/CRA Computing Innovation Fellow
> =================================================================
> Center for Ultra-scale Computing and Information Security (CUCIS)
> Department of Electrical Engineering and Computer Science
> Northwestern University
> 2145 Sheridan Rd, Tech M384 
> Evanston, IL 60208-3118
> =================================================================
> Cel:   1-847-722-0876
> Tel:   1-847-491-8163
> Email: iraicu at eecs.northwestern.edu
> Web:   http://www.eecs.northwestern.edu/~iraicu/
>        https://wiki.cucis.eecs.northwestern.edu/
> =================================================================
> =================================================================
>
>   
>
>
> Ben Clifford wrote:
>>> Mathematically, the two different sequences evaluate to different values:
>>>
>>> x = y + 1
>>> y = x + 1
>>>
>>> assuming y = 0, x = 1
>>>     
>>
>> I mean in simultaneous equations (linear algebra) - in other words, "find 
>> (through whatever means you care to use) a value of x and y such that the 
>> above two equations are both satisfied" - there is no value of x and y 
>> that satisfies that.
>>
>>   

-- 
=================================================================
Ioan Raicu, Ph.D.
NSF/CRA Computing Innovation Fellow
=================================================================
Center for Ultra-scale Computing and Information Security (CUCIS)
Department of Electrical Engineering and Computer Science
Northwestern University
2145 Sheridan Rd, Tech M384 
Evanston, IL 60208-3118
=================================================================
Cel:   1-847-722-0876
Tel:   1-847-491-8163
Email: iraicu at eecs.northwestern.edu
Web:   http://www.eecs.northwestern.edu/~iraicu/
       https://wiki.cucis.eecs.northwestern.edu/
=================================================================
=================================================================


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