creating combinations in the rows of two large multi-dimensional (N-by-M) matrices

I have two large multi dimesional matrices and wanted to create the combination scenarios in row of the two matrices that combination should repeat with the number of column times.

Let

x1=2*ones(5,48);x2=3*ones(5,48);

I want to perform the following operation

Y=x1+x2

the above operation can be added directly but that is not desired here,I want to creat scenarios for the combinations in rows of x1&x2,,,,resulting matrix Y will be 25 by 48

How can I do that in matlab?

[KSSV]

we know that the number of combinations in row of the two matrices is 25?

How ?

[Samuel]

Thanks for your question,the number of rows in each matrix is 5,number of combinations will be 5^2,my desire is to create these row combinations for the number of column(48) times.

[madhan ravi]

Mind illustrating with a 2 X 2 matrix?

x1 = [1:2; 3:4]
x2 = [5:6; 7:8]

What would the result be for the above?

[Samuel]

Thanks dear madhan,sure,for the sake of understanding we can illustrate it using lower order possible matrices as u brought here:

x1=[1 2;3 4];
x2=[5 6;7 8];

purpose:to create the follwing different scenarious,

For Column 1

(1,5),(1,6),(3,5) and (3,6)

For Column 2

(3,7),(3,8),(4,7) and (4,8)

Having the above scenarious created I want to do the follwing math manipulation

Y=x1+x2

[madhan ravi]

Not clear , what happened to 2? State explicitly how Y should look like.

[Rik]

@Samuel Admas There is no way of knowing how this may be useful to a future reader. That is why we are very hesitant to delete threads. Can you explain in longer form why you think this thread should be deleted?

Answer 1

[KSSV]

Read about nchoosek, combnk.

combnk will give you indices, and using these indices you can pick the rows.

[Samuel]

Thanks for your suggestion,can you explain it more,actually ndgrid() can give us the combination but still we should do the repetation for number of column times.

x1=2*ones(5,48);
x2=3*ones(5,48);
[C1,C2]=ndgrid(x1(:,1),x2(:,1))
for c=1:48
    for ct=1:numel(C1)
    end
Y=C1(ct)+C2(ct)
    end
end

i gave a try as shown above,I am looking help to improve the above trial,

Thanks in advance!

[KSSV]

There would be 10 combinations, when you select 2 out of 5. nchoosek gives the number of combinations and combnk gives the possilbe combinations.

[Samuel]

Thanks but sorry,that is not clear to me and not intended to do it like that either