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Strange behavior with comment
Posted:
May 6, 2011 6:34 AM


The following gives an error,
m = 4; k = 3; IntegerPartitions[ m, {k}]; (* Get all integer partitions that are exactly of length k *) Permutations /@ %; (* Get all permutations of the integer partitions *) Flatten[%, 1] (* Flatten the list *) Apply[Multinomial, %, {1}] (* Apply Multinomial to each element of the list % *) ns = Plus @@ %
Flatten::normal: Nonatomic expression expected at position 1 in Flatten[3,1]. >>
Flatten[3, 1]
However, if I remove the comment from the entry in the line before Flatten, then it gives the correct results,
m = 4; k = 3; IntegerPartitions[m, {k}]; (* Get all integer partitions that are exactly of length k *) Permutations /@ %; Flatten[%, 1] (* Flatten the list *) Apply[Multinomial, %, {1}] (* Apply Multinomial to each element of the list % *) ns = Plus @@ %
{{2, 1, 1}, {1, 2, 1}, {1, 1, 2}}
{12, 12, 12}
36
Why does this happen?



