### Ansys Matrix Sorting and Reordering

Sorting*

The *MOPER command has a sort which can be quite convenient. Here's an example of sorting the matrix of different columns consecutively.

/PREP7
! Creates Matrix
*dim, mymatrix, array, 5, 3
mymatrix(1, 1) = 4
mymatrix(2, 1) = 7
mymatrix(3, 1) = 4
mymatrix(4, 1) = 1
mymatrix(5, 1) = 4

mymatrix(1, 2) = 42
mymatrix(2, 2) = 78
mymatrix(3, 2) = 42
mymatrix(4, 2) = 16
mymatrix(5, 2) = 22

mymatrix(1, 3) = 3
mymatrix(2, 3) = 8
mymatrix(3, 3) = 2
mymatrix(4, 3) = 6
mymatrix(5, 3) = 5

! Writes Original Matrix
*cfopen, origmatrix, txt
*vwrite, mymatrix(1,1), mymatrix(1,2), mymatrix(1,3)
(E20.5, ' ', E20.5, ' ', E20.5)
*cfclos

The original "mymatrix" is:
4 42 3
7 78 8
4 42 2
1 16 6
4 22 5

! Reorder Matrix by first column, then second, then third
*dim, ordering,,5 ! Ordering index array
*moper, ordering(1), mymatrix(1,1), sort, , 1,2,3 ! ordering column

! Writes Sorted Matrix
*cfopen, newmatrix, txt
*vwrite, mymatrix(1,1), mymatrix(1,2), mymatrix(1,3)
(E20.5, ' ', E20.5, ' ', E20.5)
*cfclos

The new "mymatrix" that is sorted is now:
1 16 6
4 22 5
4 42 2
4 42 3
7 78 8

The ordering array contains the initial row position which could be useful if the matrix is to be put back together. "ordering":
4
5
3
1
2

Note that *VWRITE cannot be run within the GUI but must be called from a file using /INPUT or *USE. The Ansys script can be found here [Link].

1. Hi Jason, your pages are nice inputs for someone involved in APDL. I have a small question, do you have any idea why the last column above, 3rd col, is not sorted whereas others are sorted. You mention in the comment that it sorts by first, then second and then third column but this does not happen. The result should be different if you sort according to col 3 at the end but indeed ANSYS gives the result you printed, I am a bit confused... Thx

1. Hi Umut, The third column is sorted as well. This can be found in the third and fourth row, "2" comes before "3". Kind regards, Jason

### ANSYS User Defined Results

There is an abundant of options in ANSYS classic when one wishes to post process results. ANSYS workbench default pull down menu post processing options are more limited but they can still be accessed via the User Defined Results. One way not commonly used but can come in handy is as follows: Zeroth: Under Analysis Settings, there is "Output Controls" where you can toggle to "Yes" what you would like to save before the solution starts. This is like OUTRES in APDL. Output Controls First: After solving the model, click on Solution in the tree to highlight it. Solution Second: Click on Worksheet in the toolbar. Worksheet Third: In the worksheet, you will see list of results that are saved. Right click on it to create the User Defined Results. Create User Defined Results So here we have it. You could of look up the different expressions in the help document but I find this method of accessing the results convenient.  Example: Aspec

### Export Stiffness Matrix from Ansys

It is sometimes useful to extract the mass and stiffness matrix from Ansys.     *SMAT, MatK, D, IMPORT, FULL, file.full, STIFF       *PRINT, matk, matk, txt Exporting mass matrix would be similar:       *SMAT, MatM, D, import, full, file.full, MASS The above script uses APDL Math to get the job done. (Please see previous post for another example). The ordering of the matrix is unfortunately not concurrently exported. To verify the sequencing is as expected, we will work to replicate a truss example in the  Finite Element Trusses course notes by Bob Greenlee. Figure 1: Truss Problem Setup Model Creation Script to create model: /prep7 !! Creates Model to reflect course notes ! Properties et ,1,1  mp , ex, 1, 29.5e6 r , 1, 1 ! Geometry n ,1 $n ,2, 40$  n ,3, 40, 30 $n ,4, 0, 30 e ,1,2$  e ,2,3 $e ,1,3$  e ,3,4 ! Boundary Conditions d ,1,ux,0 $d ,1,uy,0 d ,2,uy,0 d ,4,ux,0$  d ,4,uy,0 f ,2,fx,20e3 f ,3,fy,-25e3 ! solves /solu eqslv , sparse