combination and their sum

hi can you help me with this

4 2

5 7

3 1

Combination 1: 4,5,3

Combination 2: 4,5,1

Combination 3: 4,7,3

Combination 4:2,5,3

Combination 6: 2,7,1

Combination 7: 2,7,3

Combination 8: 2,5,1

Combination 9: 4,7,1

And sum of each combination

thanks

Answer 1

[the cyclist]

A = [4 2;
     5 7;
     3 1];

m = size(A,1); 

output = [];
for j = 1:2
    output = [output; A(:,j)'];
for i  = 1:m
    output = [output; [A(1:i-1,j); A(i,3-j); A(i+1:end,j)]'];
end
end

sumOutput = sum(output,2)

This will work for any number of rows, but only for 2 columns.

[sampath kumar punna]

A = [1 2;

1 2;

1 2

1 2];

m = size(A,1);

output = [];

for j = 1:2

output = [output; A(:,j)'];

for i = 1:m

output = [output; [A(1:i-1,j); A(i,3-j); A(i+1:end,j)]'];

end

end

sum=output

sumOutput = sum(output,2)

if you could run this code you can see

this code is missing few combinations like

1 1 2 2

1 2 1 2

1 2 2 1

2 2 1 1

2 1 2 1

2 1 1 2

took 1 and 2 digits to understand combinations clearly.

Is it possible to fix the above error?

Can I get a code for n rows and n columns?

Answer 2

[Bruno Luong]

A = [4 2;
     5 7;
     3 1]
 
m = size(A,1);
b = dec2bin(0:2^m-1,m)-'0';
C = A((1:m)+m*b).'

Result (each column is a combination)

C =

     4     4     4     4     2     2     2     2
     5     5     7     7     5     5     7     7
     3     1     3     1     3     1     3     1

Nest you can sum C by

>> sum(C)

ans =

    12    10    14    12    10     8    12    10