Permutations and Combinations

Hi --

Is there a standard Smalltalk way to enumerate the possible permutations
and combinations of a collection of collections?  I'm not having any
luck googling for an example or mention of a class or package to use.
I'm trying to minimize a non linear cost function and want to calculate
the set of costs.  The collection of collections can have any number
greater than two collections in it and those collections are of varying
size.  

Thanks

Paul
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On 12.03.2010, at 15:27, Paul DeBruicker wrote:
>
> Hi --
>
> Is there a standard Smalltalk way to enumerate the possible permutations
> and combinations of a collection of collections?  I'm not having any
> luck googling for an example or mention of a class or package to use.

Type "permut" somewhere. Select, press Cmd-Shift-W. You'll see a few candidates :)

- Bert -


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Ahh.  Thanks.  Thats helpful.  


An illustration of what I want is:

|w x y z |
w:=OrderedCollection with: 'A'
x:=OrderedCollection with: 'a' with: 'b' with: 'c' with: 'd'.
y:=OrderedCollection with: '1' with: '2' with:'3'.
z:=OrderedCollection with: x with: y.

from z I want to get
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
#('A' 'a' '1')
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Sorry.  I hit send inadvertently.  


 
 
 An illustration of what I want is:
 
 |w x y z |
 w:=OrderedCollection with: 'A'
 x:=OrderedCollection with: 'a' with: 'b' with: 'c' with: 'd'.
 y:=OrderedCollection with: '1' with: '2' with:'3'.
 z:=OrderedCollection with: w with: x with: y.
 
from z I want to get
 #('A' 'a' '1')
 #('A' 'b' '1')
 #('A' 'c' '1')
 #('A' 'd' '1')
 #('A' 'a' '2')
 #('A' 'b' '2')
 #('A' 'c' '2')
 #('A' 'd' '2')
 #('A' 'a' '3')
 #('A' 'b' '3')
 #('A' 'c' '3')
 #('A' 'd' '3')

The permut* functions you helped me find seem to make the permutations
of the collections, but not the contents of the collections.  
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On 12.03.2010, at 16:28, Paul DeBruicker wrote:
Now that looks like simple nested iterations, not permutations:

Array streamContents: [:s |
        #('A') do: [:a |
                #('a' 'b' 'c' 'd') do: [:b |
                        #('1' '2' '3') do: [:c |
                                s nextPut: {a. b. c}]]]]

- Bert -


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