45 lines
822 B
Python
Executable File
45 lines
822 B
Python
Executable File
# Tuple module
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#
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# tuplesDo generates all unordered sets (in a list) of size n of the
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# elements of the list l. The resulting lists (of length n) are passed
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# to the function f.
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# First some generic combinatorial stuff
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def faculty_gen(n,k):
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if n <= k:
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return 1
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else:
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return n * faculty_gen(n-1,k)
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def faculty(n):
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return faculty_gen(n,1)
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def binomial(n,k):
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b1 = faculty_gen(n,k)
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b2 = faculty(n-k)
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return b1/b2
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# How many elements will there be?
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def tuples_count (l,n):
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return binomial(l,n)
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# Generate those elements, and apply f
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def tuples_do (f,l,n):
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def recurse (l,r):
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if r and (len(r) == n):
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f(r)
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else:
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if l and (n > 0):
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# Larger size: we have options
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# Option 1: include first
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recurse (l[1:], r + [l[0]])
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# Option 2: exclude first
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recurse (l[1:], r)
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recurse (l,[])
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