XANSYS Message: 28396 [Go back to message list]
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Subject: Re: APDL: *moper,,,,,map
Author: Mike McNamee
Date: 2001-09-11 15:33:00

Rick,

This is from John Swanson's last note on the subject:

c ***** Map option (one set of nodes to another) ****
c *MOPER,ResVal(1,1),ResXYZ(1,1),MAP,InVal(1,1),InXYZ(1,1),
c kDim,Ratio,kOut
c kDim = 2, 2d 3, 3d
c Ratio = MaxElSize/MaxGridDim of input data
(autodefault) (was 0.10 default)
c kOut = 0, use closest point values 1, zero if outside

ARG8, by my count should be 'kOut' which will allow the user to control what
happens at the boundary. Right now the behavior is, I believe, to use the
nearest node value. This can make for quite a slow process. Per the prior
discussions, ANSYS is implementing a toggle to simply (and quickly) report
back a zero if it is out of bounds. Also, the beta MAP feature did not
support the *VMASK command. This is supposed to be fixed in the next
go-round, so that the zero valued interpolation points could be used in a
mask for subsequent calculations. I'm not sure what the 'Ratio' does
exactly (I haven't observed that much of a difference), but John had said
that:

"I have found that the default value of 0.10 in field 8 is much too high for
large problems. I suggest you supply a value in this field. A good value
is:

Value = 1.0 / (sqrt(nIn)), where nin is the number of nodes in the
input (known) set. (for kDim = 2)

Value = 1.0 / (cuberoot(nin)), where nin is the number of nodes in the
input set (for kDim = 3)"

I'm guessing 'Ratio' is just a characteristic length kind of value for
identifying possible elements to interpolate into. My guess is that this
would result in a speed issue rather than an accuracy issue, although I
didn't note that much of a difference in what I was doing. I did attempt to
interpolate at a few 'known' positions and the interpolation was as accurate
as my calculator could predict.

Hope this helps.

Sincerely,
Mike McNamee
PADT

Michael R. McNamee
Analytical Engineer
CFD & Multi-Discipline Simulation
Phoenix Analysis & Design Technologies
1465 N. Fiesta Boulevard, Suite 107
Gilbert, AZ 85233

mike.mcnamee@p...
www.padtinc.com

Phone: (480) 813-4884
Fax: (480) 813-4807

-----Original Message-----
Sent: Tuesday, September 11, 2001 11:00 AM
To: xansys

I have a couple of questions regarding the map function on the *moper
command:

1. What is the significance of the ratio value in field 8? I've played
with different settings and can't see any effect. Is this an accuracy or
speed issue?

2. What is currently being done with nodes outside the region? It sounded
like from previous posts that they were assigned values from nearest nodes.
Nearest in the original set or nearest of the mapped nodes?

Rick Fischer
Marconi Communications, Inc.

Posts possibly associated with message #28396AuthorDateScore
28394APDL: *moper,,,,,mapRick Fischer2001/09/11 
28396Re: APDL: *moper,,,,,mapMike McNamee2001/09/11 
28397Re: APDL: *moper,,,,,mapRick Fischer2001/09/11 
28401Re: APDL: *moper,,,,,mapMike McNamee2001/09/11 
28418Re: APDL: *moper,,,,,mapRick Fischer2001/09/12 
28423Re: APDL: *moper,,,,,mapRick Fischer2001/09/12 
28425Re: APDL: *moper,,,,,mapRick Fischer2001/09/12 
85587APDL-*MOPER,,,MAPCOLOMBET David NEERFT (AREVA NP SAS) 2006/12/0510
85593Re: APDL-*MOPER,,,MAPRicardo Moraes2006/12/05