On 11/06/2012 07:14 PM, jerro wrote:
In general I like the API in file normal.d attached to your original post. I
think the engines should have an option to do some initialization in Normal's
constructor, though. We could achieve that by calling _engine.initialize in
Normal's constructors, if such method exists.
What's wrong with such initialization being in the constructor of the relevant
NormalEngine? I think that was your original idea, and I derailed it because of
my misunderstanding of what you wanted to initialize.
The users would need to construct their own instance of engine to use the
function that takes engine as a parameter. So it would make sense to add helper
functions for creating engine instances.
In general the idea is that the engine should be something hidden; where you
need to use it, you just need to pass the name as a template parameter; it
should be rare that you really need to manually instantiate your own engine.
But we can add such a helper function if you like.
What I'm frustrated about is that as-is it's not possible to just have
auto nrng = Normal(mean, sigma);
... but you have instead to write,
auto nrng = Normal!()(mean, sigma);
despite the fact that Normal has default template parameters given. So maybe a
helper function normalRNG which returns an instance of Normal would also be helpful.
There's one change that I think would make the API more convenient. Normal
struct and the engine don't store an instance of a RNG , so they don't need to
take it as a template parameter. We could make opCall methods templates instead.
That way the users would never need to explicitly specify the type of the RNG.
Good call.
I've uploaded a tweaked version based on your comments here:
https://github.com/WebDrake/phobos/tree/normal
... so feel free to pull, further revise and add in your Ziggurat
implementation :-)
I haven't yet written any of the helper functions you suggest, but will do so
shortly based on your response to my above remarks.
