Defining functions in PyMAPDL

[ememe123]

Hello, I am translating some of my APDL code to PyMAPDL and am struggling with the part where I need to define a function. I use that function to apply temperature on all nodes in my meshed geometry with the function t = 10*X. So each node has a temperature equivalent to 10 times the X position.
How I did it in APDL was using Function tool (in GUI) as I couldn't find any documentation how do do it in code (checked also Ansys Basic Analysis Guide where they only go over how to use a Function tool in GUI).

What I did in APDL at the end was:

1. Use function tool to define my function: 10*{X}
2. Save function to path (local)
3. Load function to ANSYS (read from file)
4. Open Session editor and copy that part of code to my APDL code

The thing is that ANSYS does some tabular representation of this rather simple function which I don't understand at all. This is from session editor:

*SET,_FNCNAME,'fun_1'
*SET,_FNCCSYS,0
UNDO,MARK
! /INPUT,fun_1.func,,,1
*DIM,%_FNCNAME%,TABLE,6,3,1,,,,%_FNCCSYS%
! Begin of equation: 10*{X}
*SET,%_FNCNAME%(0,0,1), 0.0, -999
*SET,%_FNCNAME%(2,0,1), 0.0
*SET,%_FNCNAME%(3,0,1), 0.0
*SET,%_FNCNAME%(4,0,1), 0.0
*SET,%_FNCNAME%(5,0,1), 0.0
*SET,%_FNCNAME%(6,0,1), 0.0
*SET,%_FNCNAME%(0,1,1), 1.0, -1, 0, 10, 0, 0, 2
*SET,%_FNCNAME%(0,2,1), 0.0, -2, 0, 1, -1, 3, 2
*SET,%_FNCNAME%(0,3,1), 0, 99, 0, 1, -2, 0, 0
! End of equation: 10*{X}``

I just copied that part in APDL and it worked but I would really like something cleaner now when writing it in PyMAPDL. What is even going on here, why is the table 6,3,1. Appreciate help.

[mikerife]

Hi @ememe123
That function tool is really only meant to be used in Mechanical APDL in interactive mode. The commands you show are how MAPDL stores the function and is not meant to be read/edited by a human....well, at least not easily readable.

Why not instead build your own table and use a loop to fill out values based on the equation. You could start by *VGET to get the X location of each node, then *TOPER to fill the second column with 10x the first columns values.

Mike

[ememe123]

Thank you. I don't know why I was complicating it. Looping through nodes will work just fine.

[germa89]

Hi @ememe123

If I were you I would be a bit more pythonic... For instance:

mapdl.nsel(..)  # Select the nodes you want


def apply_temp(node_id):
    x = mapdl.get_value("node", node_id, "loc", "x")

    # apply temp
    mapdl.d(node_id, "temp", 10*x)

for each_node in mapdl.mesh.nodes:
     apply_temp(each_node)

Please double check the above code, because I'm writing from the top of my head. But I think you get the point.

[ememe123]

Perfect, makes much sense, thank you!