Forgive me if this a redundant post, I don't think my original message made
it through to the list.

I'm not getting the performance that I would expect out of the
FastValueGridPortrayal2D with an immutable field. I've attached an example
class that demonstrates the issue. The portrayal's field is a DoubleGrid2D
that has random values between 0 and 1, mapped from translucent black to
opaque black. Every 50 steps the values on the grid are reset to new random
values. It seems to me that I should be able to get the best performance by
calling setImmutable(true) on the portrayal, and calling reset() every 50
steps. By "better performance" I mean the simulation steps faster.

However, I don't have any noticable improvement if setImmutable is true or
false. It doesn't seem to matter if the buffer is set to USE_BUFFER or
DONT_USE_BUFFER. If the colors are mapped from opaque white to opaque black
(so there is no transparency), performance is much better, but ONLY if I set
immutable to false. Doesn't that seem backwards?  

I feel like I must be missing something about how setImmutable works. Any
suggestions? I'm using WinXP with the most recent version of MASON.

And a mostly unrelated question: Is there any reason you can detatchAll()
from a Display2D but not detatch a specific portrayal?

Thanks, and congrats on the new version,
Marc