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World: r4wp

[Rebol School] REBOL School

caelum
27-Feb-2013
[1669]
I just copied all the SDK stuff back onto my main HD and I found 
view.r. Thanks for that GrahamC. I'll retry encapping my program 
with the includes..
caelum
28-Feb-2013
[1670]
I have included view.r and now have the graphical elements working 
after 'enface', thanks GrahamC. But I'm still getting the other errors: 
This is all to do with setting up the email parameters:

    Set-Net not provided.

    ** Access Error: Invalid port spec: scheme pop user [me-:-mydomain-:-net] 
    pass PASSWORD host mail.mydomain.net

    ** Near: open [scheme: 'pop user: "[me-:-mydomain-:-net]" pass: "PASSWORD" 
    host: "mail.mydomain.net"]
GrahamC
28-Feb-2013
[1671]
If you did a grep on your source directory you'll find it ... in 
prot-setnet.r
caelum
28-Feb-2013
[1672]
I found set-net in prot-setnet.r and included it with the same includes 
of GrahamC above, and now I get this error:

** Script Error: Invalid path value: pop
** Where: forskip
** Near: forall settings [
    if (item: first settings) = 'none [item: none] 
    if word? item [item: form item] 
    do first ...


Not sure where to go from here as I don't know what I am looking 
at in terms of errors.
GrahamC
28-Feb-2013
[1673]
show us your include files
caelum
28-Feb-2013
[1674]
Same as yours only with prot-setnet.r added.

#include %gfx-colors.r
#include %gfx-funcs.r

#include %view-funcs.r
#include %view-vid.r
#include %view-edit.r
#include %view-feel.r
#include %view-images.r
#include %view-styles.r
#include %view-request.r

#include %prot-setnet.r


;-- Must be done prior to loading anything that requires fonts on 
Linux.

layout [text "imanXwin kludge"] ;-throw this one away soon-- okay?

open-events
GrahamC
28-Feb-2013
[1675x3]
you don't have any protocols
you need to include prot.r
and then remove prot-setnet.r or just add the protocols you need
caelum
28-Feb-2013
[1678]
Got it! Now I see how it all works and I have 'enface' working on 
linux. Many Thanks for your help!
NickA
10-Mar-2013
[1679]
What's the proper (fast) way to do this?

    REBOL [title: "Anagram List"]
    a: copy []
    mix: func [str prev] [   
        repeat i length? str [
            picked: pick str i
            rest: head remove at copy str i
            append a rejoin [prev picked rest]
            mix rest join prev picked
        ]
    ]
    mix input: ask "Text:  " ""
    editor unique a
Sunanda
11-Mar-2013
[1680]
Don't know if it is faster or more proper, but it's another way:
   http://www.rebol.org/view-script.r?script=lexpem.r
Steeve
11-Mar-2013
[1681]
res: copy [ ] 
    mix: func [str /local i][
    	if 1 = i: length? str [append res copy head str exit]
    	loop i [
    		append str str/1
    		mix next remove str
    	]
    ]
MaxV
11-Mar-2013
[1682x4]
Just use math:
a: copy []

mix: func [ myword /local n t] [
	n:  length? myword
	t: 1
	loop n [ 
		t: n * t 
		n: n - 1
		]	
	while [(length? a) < t] [
		append a random myword	
		unique a
	
		]
	a	
	]
mix "test"

editor a
I think that it's quicker, since you don't mess with series altering, 
insted you just create mixed words enough to reach the maximum available 
permutations.
For short words...
:-P
NickA
11-Mar-2013
[1686x2]
Thank you guys.  Steve, that's much quicker.  There's no way that 
succeeds without the exponential increase in evaluation, with each 
added character?  I was hoping there might be some magic to learn...
Steve, that code doesn't appear to create all the possible anagrams.
Steeve
11-Mar-2013
[1688x2]
for instance ?
/me pouring a glass of whisky
NickA
11-Mar-2013
[1690x2]
REBOL [title: "Anagram List"]


a:[]m: func[s p][repeat i length? s[append a rejoin[p k: s/:i r: 
head remove at copy s i]m r join p k]]m ask""""editor unique a probe 
length? a


a:[]m: func[s /local i][if 1 = i: length? s[append a copy head s 
exit]loop i[append s s/1 m next remove s]]m ask""editor a probe length? 
a

halt
Mine is the first one, yours is the second.
Steeve
11-Mar-2013
[1692]
can you give a test case where mine is faling ?
NickA
11-Mar-2013
[1693]
Try each line above.  Mine gives 325 anagrams for "asdfg".  Yours 
is much faster, but only results in 120 anagrams for the same input 
string.
Steeve
11-Mar-2013
[1694]
For a 5 letters word, the number of combinations should be 5! (factorial 
5) which gives 120.
NickA
11-Mar-2013
[1695x3]
never mind - stupid me.  didn't count the unique results in mine.
<-- bows low, and walks away :)
I still have the same question though - is there any way to evaluate 
this without the exponential increase in loop counts?
Ladislav
11-Mar-2013
[1698x2]
Nick, it would be actually nice if it was just "exponential growth". 
But the number of permutaions of N elements is N! (N factorial), 
which grows faster than the exponential function.
typo: "permutations"
NickA
11-Mar-2013
[1700]
So there's no way of reducing this problem beyond N! ?
Ladislav
11-Mar-2013
[1701x2]
How can you produce N! distinct results without producing N! distinct 
results?
(there is no way)
NickA
11-Mar-2013
[1703x3]
I was hoping to discover some ignorance on my part about the problem.
Thank you for the definitive answer Ladislav, and thanks for the 
code Steeve
(I was hoping that there was perhaps some sort of parallel processing 
solution or some sort of advanced math magic that I knew nothing 
about)
Ladislav
11-Mar-2013
[1706]
Aha, but Steeve's algorithm looks like being slower than O(N!), if 
I understand it well.
Sunanda
11-Mar-2013
[1707]
Nick -- sounds like you want an algorithm that, say, returns the 
next 50 -- that way you can work with a window rather than have to 
generate all perms in one gulp. Some of the offered solutions should 
be easily adaptable in that way.
NickA
11-Mar-2013
[1708x2]
Ladislav, can you make one which performs faster than Steeve's?


Sunanda, paging through windows of is a great way to be practical. 
 I'm more concerned with finding the fastest algorithm - no reason 
- just frustrated with myself for sitting last night for longer than 
I wanted with a CS101 type problem ;)
Just out of curiosity, has anyone written a difinitive article about 
the performance of various looping structures in REBOL?  I remember 
some discussion about it several years ago, related to how badly 
REBOL did in the language "shootout" benchmarks (lots of  "for'" 
loops, if I remember correctly).  That would be a nice article to 
have available.
GrahamC
11-Mar-2013
[1710]
Nick, the issue is many of the looping constructs were mezzanine...
BrianH
11-Mar-2013
[1711x2]
For R2: native loops are faster than mezzanine (function) loops, 
so much faster that their individual differences amongst themselves 
are almost irrelevant. For R3 all loops are native (except FIND-ALL, 
temporarily), so the big difference is one-time-per-call bind/copy 
overhead for binding loops, versus not having that for non-binding 
loops.
LOOP is the fastest limited scope loop.
NickA
11-Mar-2013
[1713]
I always noticed that Carl used more "while" structures than I w
BrianH
11-Mar-2013
[1714x4]
For R2 I would use LOOP, REPEAT, FOREACH or WHILE whenever possible. 
In R3, REPEAT and FOREACH have bind/copy overhead, while FORALL and 
FORSKIP don't, so the latter can be faster in many cases. WHILE and 
LOOP are the same in R3 as they were in R2, at least relative to 
the other native loops.
FOR has bind/copy overhead in R3 and is a complex mezzanine in R2, 
so I only use it when it is really appropriate.
UNTIL is native in both too, basically a slightly simplified WHILE.
R3 is currently missing anything like the feature that made it possible 
to write really well-integrated mezzanine control structures, instead 
turning all such control structures into natives. Which was a problem 
before R3 was open sourced, not as much of one now.
Sunanda
11-Mar-2013
[1718]
Nick -- Have you looked at using a variable base algorithm? It may 
be fast, and it should be amenable to windowing:
   http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Even if neither, it should be fun to write the script.