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From: Jim Apple (japple_at_[hidden])
Date: 2003-12-12 19:03:49

Beman Dawes wrote:
> This may be a stupid question, since I've no experience with the caching
> of math function results, but do you propose to build memoization on top
> of a general cache facility?

By cache facility, I assume you mean some sort of associative container.
  If instead you're talking about serialization/persistence, then I
agree that memoization would benefit from that. Over different
invocations of an application, a function becomes more lookup and less
function? Faboo! Do I think this is necessary for memoization to be very
useful? No.

Now, assuming you're talking about associative containers

The present prototype takes a type parameter memo_wrap, that, in turn,
takes a type parameter. At present, memo_wrap is specialized only for
map, but a specialization for std::unordered_set would be good, and the
interface would support a container that optimizes access for most
accessed objects.

> If so, would it make sense to work on the cache facility first?

First? I don't think so. It yields big advantages for simple containers
like std::map.

Should a cache facility be developed? I DO think so. It would certainly
yeild advantages to memoization

> Also, would there be any benefit in specifying the cache facility as a
> memoization policy, so that different caches with different performance
> characteristics could be supplied according to user needs?


> I do have considerable experience with the caching of the results of
> search function, and have seen or read about various situations:
> [snip]

These results would be very helpful if built into different cache types.
   These benefits would show up in memoization mostly for non-recursive

> Given all that variability, policy-based caching might be very attractive.

I agree strongly.


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