Dynamic Closure + Lazy Arguments = Performance Killer?

[Frank Benoit]

Jason House schrieb:
> I ported some monte carlo simulation code from Java to D2, and
> performance is horrible.
> 
> 34% of the execution time is used by std.random.uniform. To my great
> surprise, 25% of the execution  time is memory allocation (and
> collection) from that random call. The only candidate source I see is
> a call to ensure with lazy arguments. The memory allocation occurs at
> the start of the UniformDistribution call. I assume this is dynamic
> closure kicking in.
> 
> Can anyone verify that this is the case?
> 
> 600000 memory allocations per second really kills performance!

It was written in this NG over and over. The D2 full closure feature is
a BIG!!!! problem.

The nested functions passed as callback are an important and performance
technique in D. The D2 full closure "feature" effectively removes it and
makes D2 less attractive IMHO.