how to add the first row all the odd columns by step of 2 odd columns

I want to add 1 and 3 the 2 and 1. Then moving to second row I want to add 1 and 1 then 4 and 5. Similarly I want to, in general, using using loop for an image

a = [...    
       1     2     3     1
       1     4     1     5
       5     8     5     9
       1     9     2     1]

[madhan ravi]

What’s your required output ? Can you give an example?

[juveria fatima]

i want to add first column with third ,then fifth column to be added with seventh in short (i want to add all the odd columns) then even columns to added

Answer 1

[madhan ravi]

Try this:

a1=a(:,1:2:end) %for odd columns 

a2=a(:,2:2:end) %for even columns

oddcolumns=sum(a1,2)

evencolumns=sum(a2,2)

a

[madhan ravi]

If it’s not upto the expectations let me know.

[juveria fatima]

i have to solve two problems to explain my problem clearly i made a slide kindly review

[madhan ravi]

The updated code gives you the result as expected now.

[juveria fatima]

as per results evencolumn sum should be

3
9
17
10

a =

     1     3
     1     1
     5     5
     1     2

a1 =

     3
     1
     5
     2

oddcolumns =

     4
     2
    10
     3

evencolumns =

     3
     1
     5
     2

[madhan ravi]

That’s the result I’m getting.

[madhan ravi]

a =

       1     2     3     1
       1     4     1     5
       5     8     5     9
       1     9     2     1

a1 =

       1     3
       1     1
       5     5
       1     2

a2 =

       2     1
       4     5
       8     9
       9     1

oddcolumns =

       4
       2
      10
       3

evencolumns =

       3
       9
      17
      10

>>

[juveria fatima]

thank you i got it

[madhan ravi]

did you check the code which was updated?

[juveria fatima]

can you please help me out with second binary image example in above pdf attached

[madhan ravi]

Sorry I have no experience with that unfortunately

[juveria fatima]

ok can you do the inverse of the above updated code i want to get the matrix a back

[madhan ravi]

Like can you type the required result and post it here? So that I could understand what should be done?

[juveria fatima]

from the obtained result

oddcolumns =

       4
       2
      10
       3

evencolumns =

       3
       9
      17
      10

i want to get back the input a i.e

a =

       1     2     3     1
       1     4     1     5
       5     8     5     9
       1     9     2     1

[madhan ravi]

Check the updated code.

[juveria fatima]

consider this as encoding code where a is encoded as odd columns and even columns

        a=[1 2 3 1;1 4 1 5;5 8 5 9;1 9 2 1]  
        a1=a(:,1:2:end) %for odd columns 
        a2=a(:,2:2:end) %for even columns
        oddcolumns=sum(a1,2)
        evencolumns=sum(a2,2)

now i want its inverse i.e decoding back to a ( output should be a )