HOW TO ACCESS THE FOLLOWING ELEMENTS FROM THE GIVEN ARRAY

a=

       0         0      0.3013    1.1305
    1.0000    2.0000    0.7390    0.4223
    3.0000    2.0000    1.1305   -0.2111
I need

A1=[[a(1,1) a(2,1) a(1,3) a(2,3)]' [a(1,2) a(2,2) a(1,4) a(2,4)]' ] A2=[[a(2,1) a(3,1) a(2,3) a(3,3)]' [a(2,2) a(3,2) a(2,4) a(3,4)]' ]

[Cedric]

What doesn't work with the current approach? Do you need to generalize it to larger arrays? If so, what will be the size of these arrays and what will you want to perform ultimately?

[BIRAJA]

Sir,

I want to access the elements of the given matrix as per the sequence. It can be increased to 50-rows and 50-columns. I want a generalized code.

Answer 1

[Andrei Bobrov]

A1 = reshape(permute(reshape(a(1:end-1,:),2,2,[]),[1,3,2]),[],2);

a02 = [a(:,2:end-1);a(2:end,end)'];
A2 = reshape(permute(reshape(a02',2,2,[]),[1 3 2]),[],2);

Answer 2

[George Papazafeiropoulos]

a=[       0         0      0.3013    1.1305;
    1.0000    2.0000    0.7390    0.4223;
    3.0000    2.0000    1.1305   -0.2111];
A1=[[a(1,1) a(2,1) a(1,3) a(2,3)]' [a(1,2) a(2,2) a(1,4) a(2,4)]' ]
A2=[[a(2,1) a(3,1) a(2,3) a(3,3)]' [a(2,2) a(3,2) a(2,4) a(3,4)]' ]

for i=1:size(a,1)-1
    b=a(i:i+1,:);
    b=b(:);
    n1=1:size(a,2)-1;
    b1=b;
    ind1=3+cumsum([0,2+(-1).^n1]);
    b1(ind1)=[];
    b2=b;
    ind2=1+cumsum([0,2+(-1).^n1]);
    b2(ind2)=[];
    A=[b1 b2]
end