Questions tagged [permutation]
For questions about the functionality related to permutations in Mathematica.
56
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How to represent a list as a cycle
I want to select distinct cycles (represented by List).
The cycle {a, b, c, d} must be the same as {b, c, d, a} or ...
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votes
7
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Permutations[Range[12]] produces an error instead of a list
This input:
Permutations[Range[12]]
Results in this (error) output:
...
- 1,017
15
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3
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Find all permutations with a condition
How can I find all the permutations of {a, b, c} where a + b + c = n?
For instance: if n = 3...
- 253
34
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9
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Faster derangements?
I wonder what is the fastest method to generate derangements?
Both the Combinatorica function and Martin Ender's answer to Permutations of lists of fixed even numbers are based on filtering the ...
- 272k
21
votes
4
answers
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Optimization of function taking a permutation
I have a function $f$ which takes a permutation $P$ of the integers 1-100 in order to give a numerical value $f(x)$. The function is given by a black box, but is relatively "smooth", so should be ...
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16
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1
answer
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ls Ordering[Ordering[list]] optimal?
Given a list list with unique elements, the task is to replace each element by its position in Sort[list]. For example,
...
- 48.8k
13
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4
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575
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Equivalent Nested Loop Structure (combinations_with_replacement)
Consider the following examples:
...
- 5,662
14
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4
answers
5k
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How to remove repeated permutations?
I want to get the Permutations on the elements of a list. Then I'm doing this:
...
- 5,411
0
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1
answer
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Set conditions at a permutation
I need to find all permutations of 3 elements from {a,b,c,d,e} with this condition: These must include element d maximum once, ...
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Fastest way to generate {{a,a},{a,b},{a,c},{b,b},{b,c},{c,c}} from {a,b,c}
What is the fastest way to generate {{a,a},{a,b},{a,c},{b,b},{b,c},{c,c}} from l={a,b,c}? I've tried
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6
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2
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Challenge: Creating Compilable Permutations Function
As Mathematica's implemented Permutations function is not compilable, I tried to write my very own Permutations implementation, ...
- 2,720
5
votes
4
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492
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Sort two lists at the same time, based on another
I am new to using Mathematica and I can not find a solution to what I am wanting to do.
I want to take a list such as:
x = {1,2,3,4,5,6,7,8}
and a second list (...
- 143
22
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3
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Generating Tuples with restrictions
I am interested in a certain subset of all tuples. Generating all with Tuples and then filtering is wasteful, and will "blow up" very quickly.
For a concrete ...
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14
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2
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What is the fastest way to get the nth distinct permutation of a list?
What is the fastest way to write a function nthPermutation[xs_List, n_Integer] which is equivalent to Permutations[xs][[n]] but ...
- 2,336
14
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1
answer
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How to apply a permutation to a symmetric square matrix?
Given a symmetric square matrix, how can I apply a permutation to the rows and columns (i.e. the same permutation to both the rows and the columns) such a way that the new structure of the matrix ...
- 47.1k