Alter number sort / number sequence










4















I have an array / number sequence a=[1,2,3,4,5] and I'm trying
to create an array / number sequence that looks like a_new below:
The columns represent the orders / index the numbers should go in.



a_new=...
[1,2,3,4,5;
2,1,2,3,4;
3,3,1,2,3;
4,4,4,1,2;
5,5,5,5,1]


My thoughts where to use circshift but quickly found out that would not work.



a=[1,2,3,4,5];
for n=1:5
a_wrong(:,n)=circshift(a(:)',[0 n])(:)
end


produces



a_wrong=[
5 4 3 2 1
1 5 4 3 2
2 1 5 4 3
3 2 1 5 4
4 3 2 1 5]


Any thoughts? It doesn't need to use circshift if that won't work.



PS: I'm using Octave 4.2 which is similar to Matlab










share|improve this question
























  • can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

    – Ander Biguri
    Nov 13 '18 at 17:11











  • @AnderBiguri the columns represent the orders / index the numbers should go in.

    – Rick T
    Nov 13 '18 at 17:17















4















I have an array / number sequence a=[1,2,3,4,5] and I'm trying
to create an array / number sequence that looks like a_new below:
The columns represent the orders / index the numbers should go in.



a_new=...
[1,2,3,4,5;
2,1,2,3,4;
3,3,1,2,3;
4,4,4,1,2;
5,5,5,5,1]


My thoughts where to use circshift but quickly found out that would not work.



a=[1,2,3,4,5];
for n=1:5
a_wrong(:,n)=circshift(a(:)',[0 n])(:)
end


produces



a_wrong=[
5 4 3 2 1
1 5 4 3 2
2 1 5 4 3
3 2 1 5 4
4 3 2 1 5]


Any thoughts? It doesn't need to use circshift if that won't work.



PS: I'm using Octave 4.2 which is similar to Matlab










share|improve this question
























  • can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

    – Ander Biguri
    Nov 13 '18 at 17:11











  • @AnderBiguri the columns represent the orders / index the numbers should go in.

    – Rick T
    Nov 13 '18 at 17:17













4












4








4








I have an array / number sequence a=[1,2,3,4,5] and I'm trying
to create an array / number sequence that looks like a_new below:
The columns represent the orders / index the numbers should go in.



a_new=...
[1,2,3,4,5;
2,1,2,3,4;
3,3,1,2,3;
4,4,4,1,2;
5,5,5,5,1]


My thoughts where to use circshift but quickly found out that would not work.



a=[1,2,3,4,5];
for n=1:5
a_wrong(:,n)=circshift(a(:)',[0 n])(:)
end


produces



a_wrong=[
5 4 3 2 1
1 5 4 3 2
2 1 5 4 3
3 2 1 5 4
4 3 2 1 5]


Any thoughts? It doesn't need to use circshift if that won't work.



PS: I'm using Octave 4.2 which is similar to Matlab










share|improve this question
















I have an array / number sequence a=[1,2,3,4,5] and I'm trying
to create an array / number sequence that looks like a_new below:
The columns represent the orders / index the numbers should go in.



a_new=...
[1,2,3,4,5;
2,1,2,3,4;
3,3,1,2,3;
4,4,4,1,2;
5,5,5,5,1]


My thoughts where to use circshift but quickly found out that would not work.



a=[1,2,3,4,5];
for n=1:5
a_wrong(:,n)=circshift(a(:)',[0 n])(:)
end


produces



a_wrong=[
5 4 3 2 1
1 5 4 3 2
2 1 5 4 3
3 2 1 5 4
4 3 2 1 5]


Any thoughts? It doesn't need to use circshift if that won't work.



PS: I'm using Octave 4.2 which is similar to Matlab







matlab sequence octave






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 13 '18 at 17:28









Cris Luengo

19.8k52249




19.8k52249










asked Nov 13 '18 at 17:00









Rick TRick T

1,52042973




1,52042973












  • can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

    – Ander Biguri
    Nov 13 '18 at 17:11











  • @AnderBiguri the columns represent the orders / index the numbers should go in.

    – Rick T
    Nov 13 '18 at 17:17

















  • can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

    – Ander Biguri
    Nov 13 '18 at 17:11











  • @AnderBiguri the columns represent the orders / index the numbers should go in.

    – Rick T
    Nov 13 '18 at 17:17
















can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

– Ander Biguri
Nov 13 '18 at 17:11





can you explain your matrix? why is the first column a different direction than the others? Are you 100% sure this is what you want? circshift wont work because of this, the first column is a special case

– Ander Biguri
Nov 13 '18 at 17:11













@AnderBiguri the columns represent the orders / index the numbers should go in.

– Rick T
Nov 13 '18 at 17:17





@AnderBiguri the columns represent the orders / index the numbers should go in.

– Rick T
Nov 13 '18 at 17:17












3 Answers
3






active

oldest

votes


















4














There are probably quite a few different ways to generate this matrix. Here's one using the functions repmat, toeplitz, tril, and triu:



>> a_new = tril(repmat(a.', 1, numel(a)), -1)+triu(toeplitz(a))

a_new =

1 2 3 4 5
2 1 2 3 4
3 3 1 2 3
4 4 4 1 2
5 5 5 5 1





share|improve this answer
































    1














    I'm not sure about a built-in function, but this should work;



    a=[1,2,3,4,5];
    a_out = ones(length(a), length(a))
    for n=1:5
    a_out(n,:) = [n*ones(n-1),a(n:end)]
    end


    I do not have Octave or MATLAB installed on my computer, so I cannot test it. This may have a silly error, forgive me for that!






    share|improve this answer






























      1














      You can use spdiags to generate the matrix:



      n = numel(a); 
      a_new = spdiags([repmat(flip(a).',1,n); repmat(a,n-1,1)],(1-n):0);





      share|improve this answer






















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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        4














        There are probably quite a few different ways to generate this matrix. Here's one using the functions repmat, toeplitz, tril, and triu:



        >> a_new = tril(repmat(a.', 1, numel(a)), -1)+triu(toeplitz(a))

        a_new =

        1 2 3 4 5
        2 1 2 3 4
        3 3 1 2 3
        4 4 4 1 2
        5 5 5 5 1





        share|improve this answer





























          4














          There are probably quite a few different ways to generate this matrix. Here's one using the functions repmat, toeplitz, tril, and triu:



          >> a_new = tril(repmat(a.', 1, numel(a)), -1)+triu(toeplitz(a))

          a_new =

          1 2 3 4 5
          2 1 2 3 4
          3 3 1 2 3
          4 4 4 1 2
          5 5 5 5 1





          share|improve this answer



























            4












            4








            4







            There are probably quite a few different ways to generate this matrix. Here's one using the functions repmat, toeplitz, tril, and triu:



            >> a_new = tril(repmat(a.', 1, numel(a)), -1)+triu(toeplitz(a))

            a_new =

            1 2 3 4 5
            2 1 2 3 4
            3 3 1 2 3
            4 4 4 1 2
            5 5 5 5 1





            share|improve this answer















            There are probably quite a few different ways to generate this matrix. Here's one using the functions repmat, toeplitz, tril, and triu:



            >> a_new = tril(repmat(a.', 1, numel(a)), -1)+triu(toeplitz(a))

            a_new =

            1 2 3 4 5
            2 1 2 3 4
            3 3 1 2 3
            4 4 4 1 2
            5 5 5 5 1






            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Nov 13 '18 at 17:18

























            answered Nov 13 '18 at 17:11









            gnovicegnovice

            116k13231334




            116k13231334























                1














                I'm not sure about a built-in function, but this should work;



                a=[1,2,3,4,5];
                a_out = ones(length(a), length(a))
                for n=1:5
                a_out(n,:) = [n*ones(n-1),a(n:end)]
                end


                I do not have Octave or MATLAB installed on my computer, so I cannot test it. This may have a silly error, forgive me for that!






                share|improve this answer



























                  1














                  I'm not sure about a built-in function, but this should work;



                  a=[1,2,3,4,5];
                  a_out = ones(length(a), length(a))
                  for n=1:5
                  a_out(n,:) = [n*ones(n-1),a(n:end)]
                  end


                  I do not have Octave or MATLAB installed on my computer, so I cannot test it. This may have a silly error, forgive me for that!






                  share|improve this answer

























                    1












                    1








                    1







                    I'm not sure about a built-in function, but this should work;



                    a=[1,2,3,4,5];
                    a_out = ones(length(a), length(a))
                    for n=1:5
                    a_out(n,:) = [n*ones(n-1),a(n:end)]
                    end


                    I do not have Octave or MATLAB installed on my computer, so I cannot test it. This may have a silly error, forgive me for that!






                    share|improve this answer













                    I'm not sure about a built-in function, but this should work;



                    a=[1,2,3,4,5];
                    a_out = ones(length(a), length(a))
                    for n=1:5
                    a_out(n,:) = [n*ones(n-1),a(n:end)]
                    end


                    I do not have Octave or MATLAB installed on my computer, so I cannot test it. This may have a silly error, forgive me for that!







                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Nov 13 '18 at 17:19









                    SRT HellKittySRT HellKitty

                    29318




                    29318





















                        1














                        You can use spdiags to generate the matrix:



                        n = numel(a); 
                        a_new = spdiags([repmat(flip(a).',1,n); repmat(a,n-1,1)],(1-n):0);





                        share|improve this answer



























                          1














                          You can use spdiags to generate the matrix:



                          n = numel(a); 
                          a_new = spdiags([repmat(flip(a).',1,n); repmat(a,n-1,1)],(1-n):0);





                          share|improve this answer

























                            1












                            1








                            1







                            You can use spdiags to generate the matrix:



                            n = numel(a); 
                            a_new = spdiags([repmat(flip(a).',1,n); repmat(a,n-1,1)],(1-n):0);





                            share|improve this answer













                            You can use spdiags to generate the matrix:



                            n = numel(a); 
                            a_new = spdiags([repmat(flip(a).',1,n); repmat(a,n-1,1)],(1-n):0);






                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered Nov 14 '18 at 4:04









                            rahnema1rahnema1

                            10.3k2923




                            10.3k2923



























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