Passing large or complex data structures to threads

[Simen Kjaeraas]

On Sun, 26 May 2013 14:06:39 +0200, Joseph Rushton Wakeling  
<joseph.wakeling at webdrake.net> wrote:

> On 05/24/2013 04:39 PM, Simen Kjaeraas wrote:
>> First, *is* it read-only? If so, store it as immutable and enjoy free
>> sharing. If not, how and why not?
>
> I can confess that it's as simple as feeling extremely uncomfortable  
> dealing
> with immutable where it relates to any kind of complex data structure.
>
> I mean, for that double array structure I'd have to do something like,
>
> 	Tuple!(size_t, size_t)[][] dataCopy;
>
> 	foreach(x; data) {
> 		Tuple!(size_t, size_t)[] xCopy;
> 		foreach(y; x) {
> 			immutable(Tuple!(size_t, size_t)) yCopy = y.idup;
> 			xCopy ~= cast(Tuple!(size_t, size_t)) yCopy;
> 		}
> 		immutable xImm = assumeUnique(xCopy);
> 		dataCopy ~= cast(Tuple!(size_t, size_t)[]) xImm;
> 	}
>
> 	immutable dataImm = assumeUnique(dataCopy);
>
> ... no?  Which feels like a lot of hassle compared to just being able to  
> pass
> each thread the information to independently load the required data.
>
> I'd be delighted to discover I'm wrong about the hassle of converting  
> the data
> to immutable -- I don't think I understand how to use it at all well, bad
> experiences in the past have meant that I've tended to avoid it.

That looks very complex for what it purports to do.

I understand data is the original data before sharing?

If so, will that a

-- 
Simen