Help with Matrix Summations

Hi,

Below is an output from matlab. I wish to combine this into one matrix & add the three last terms of each elg_nl to the first three in the next elg_nl. How can this be done? The required solution is shown. I may also have more than 3 elg_nl, would I require a loop??

>> elg_nl

elg_nl(:,:,1) =

       0
       0
       0
      -6
      -3
       1

elg_nl(:,:,2) =

     -5.0000
      0.0000
      7.5000
     -5.0000
      0.0000
      7.5000

elg_nl(:,:,3) =

      -6
      -3
       1
       0
       0
       0

>> expected result (12x1matrix)
     0
     0
     0
   -11.0000
    -3.0000
     8.5000
   -11.0000
    -3.0000
     8.5000
     0
     0
     0

Please help, thanks

Answer 1

[Matt J]

 sum(elg_nl,3)

will produce the middle 6 elements you want. I don't know by what you rule you want it extended to 12x1, unless it's just zero padding.

[Peter cullen]

Thanks, I am trying to create a finite element code for a portal frame. The zeros indicate zero force at certain nodes and therefore are required. Any other ideas?

[Matt J]

No other ideas are required for any apparent reason. I've given you what you requested, as far as I can tell. I don't imagine you need help padding with zeros, if that's the only missing piece.

Answer 2

[Amit]

eigen_nl_expected = [eigen_nl(:,:,1);eigen_nl(:,:,3)]
eigen_nl_expected(4:9) = eigen_nl_expected(4:9) + eigen_nl(:,:,2);