Distance between all elements of row vector

So, I have 1x200 matrix, (row vector). I want to find difference (x(0)-x(1), x(0)-x(2)...) between all elements of an array. How do I do that ?

I should be having 200x200/2 values.

Answer 1

[per isakson]

Hint:

%%
row = rand(1,6);
cell2mat( reshape( arrayfun( @(jj) row(jj)-row, (1:6), 'uni', false ), [],1 ) )

outputs

ans =
         0   -0.0790   -0.0644    0.2865    0.0233    0.5075
    0.0790         0    0.0146    0.3655    0.1023    0.5866
    0.0644   -0.0146         0    0.3509    0.0877    0.5719
   -0.2865   -0.3655   -0.3509         0   -0.2633    0.2210
   -0.0233   -0.1023   -0.0877    0.2633         0    0.4843
   -0.5075   -0.5866   -0.5719   -0.2210   -0.4843         0

[Ana]

wow thank you! is there a way to differentiate zero values from x(0)-x(0) from the actual 0 difference between two elements?

[per isakson]

The x(jj)-x(jj) values are obviously on the main diagonal, but I guess that is of little help.

You could replace the x(jj)-x(jj) values by another value, e.g. NaN

%%
row = rand(1,6);
len = length(row);
dst = cell2mat( reshape( arrayfun( @(jj) row(jj)-row, (1:len), 'uni', false ), [],1 ) );
%%  
lix = logical( eye(len) ); % logical index
dst( lix ) = NaN;

then you could do things like

>> dst >= 0.5
ans =
  6×6 logical array
   0   0   0   1   0   0
   0   0   0   0   0   0
   0   1   0   1   1   1
   0   0   0   0   0   0
   0   0   0   0   0   0
   0   0   0   0   0   0   

and

   >> dst == 0

[Ana]

Can you explain me exactly what does input into arrayfun mean?

( @(jj) center(jj)-center, (1:233), 'uni', false ), some kind of for loop ?

[per isakson]

Seriously, did you read arrayfun, Apply function to each element of array ?

Yes, arrayfun performs a loop. Roughly

len = 233;
cac = cell( 1, len );
for jj = 1 : len
    cac{jj} = center(jj) - center;
end

Answer 2

[madhan ravi]

Straightforward:

row.'-row

[Ana]

I don't understand?

[madhan ravi]

Did you run the code?

[per isakson]

%%
row = rand(1,6);
c1  = cell2mat( reshape( arrayfun( @(jj) row(jj)-row, (1:6), 'uni', false ), [],1 ) );
%%
c2  = reshape(row,[],1) - row;     % The name, reshape, communicates the intent

See Compatible Array Sizes for Basic Operations

>> c2-c1
ans =
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0