Steve Wampler wrote:
> Steve Wampler wrote:
> While it uses co-expressions (lots of them, in fact), I'm pretty sure
> it wouldn't be hard to rewrite it to remove the co-expressions also.
> That would probably reduce the memory footprint significantly.
Yes, replacing the previous implementation of the Triplet class with:
global multipliers
class Triplet : Class (base, h)
method curval()
return base * multipliers[h]
end
method nextVal()
suspend base*multipliers[h +:= 1]
end
initially (baseNum)
base := baseNum
h := 1
/multipliers := [2,3,5]
end
works nicely, *has* to take less memory, and is probably faster...
(Incidently, Triplet doesn't need to subclass Class(), that's my own
little idiom.)
> ------------------------------------------------------------------------
>
> # Lazily generate the three hamming numbers that can be derived directly
> # from a known hamming number h
> class Triplet : Class (h, ce)
>
> method curval()
> return h
> end
>
> method nextVal()
> if h := @ce then {
> suspend h
> }
> end
>
> initially (baseNum)
> h := 2*baseNum
> ce := create (3|5)*baseNum
> end
>
> # Generate hamming numbers, in order. Default is first 30
> # But an optional argument can be used to generate more (or less)
> # e.g. hamming2 5000 generates the first 5000.
> procedure main(args)
> limit := integer(args[1]) | 30
> every write("\t", generateHamming(triples) \ limit)
> end
>
> # Do the work. Start with known hamming number 1 and maintain
> # a set of triplet hamming numbers as they get derived from that
> # one. Most of the code here is to figure out which hamming
> # number is next in sequence (while removing duplicates)
> procedure generateHamming()
> triplers := set()
> insert(triplers, Triplet(1))
>
> suspend 1
> repeat {
> # Pick a hamming triplet to *may* have the next smallest number
> t1 := !triplers # any will do to start
>
> every t2 := !triplers do {
> if t1 === t2 then next
> if t1.curval() > t2.curval() then {
> # oops we were wrong, switch assumption
> t1 := t2
> }
> else if t1.curval() = t2.curval() then {
> # t2's value is a duplicate, so
> # advance triplet t2, if none left in t2, remove it
> if not t2.nextVal() then delete(triplers, t2)
> }
> }
>
> # Ok, t1 has the next hamming number, grab it
> nextHamming := t1.curval()
> # Advance triplet t1, if none left in t1, remove it
> if not t1.nextVal() then delete(triplers, t1)
> insert(triplers, Triplet(nextHamming))
> suspend nextHamming
> }
> end
--
Steve Wampler -- [EMAIL PROTECTED]
The gods that smiled on your birth are now laughing out loud.
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