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Sam January 2, 2008 19:51

Interpolation (Number of mapped nodes)

I use the solution obtained from a coarse mesh, as an initial condition file for the fine mesh simulation.

Coarse mesh : Nodes = 28315 , Elements = 96546 (tet=67228, wedges=28592, pyramids=726)

Fine mesh : Nodes = 50577 , Elements = 176159 (tet=124958, prisms=50912, pyramids=889)

But the interpolation output shows that

Number of Mapped Nodes = 46295 ( 91.5%)

Number of Unmapped Nodes = 4282 ( 8.5%)

I am not able to understand how come 46295 nodes could be mapped as the the initial value file itself has only 28315 nodes.

Please throw some light on it.

Thanks a lot,


opaque January 2, 2008 23:10

Re: Interpolation (Number of mapped nodes)
Dear Sam,

The interpolator maps the nodes on the fine mesh into the coarse mesh. Otherwise, how could you interpolate the coarse mesh values into the fine mesh?

The mapped (46295) plus the unmapped (4282) adds up to 50577. That is the number of nodes in the fine mesh.

Hope it helps,


Sam January 2, 2008 23:16

Re: Interpolation (Number of mapped nodes)

Thank you very much for your reply. :)

I am under the impression that solution values (velocities, pressure etc) from a initial value file are interpolated to the definition file mesh in order to start the simulation. If that is correct (please correct me if it was wrong), and assume that the initial values file has coarse mesh and the definition file has fine mesh, then results would have been getting interpolated from the coarse mesh to the fine mesh.

I know somewhere I am overlooking the concept. It would be great if you can further help me with it.

And happy new year :)


CycLone January 6, 2008 20:51

Re: Interpolation (Number of mapped nodes)
Hi Sam,

What the solver is telling you is how many nodes were mapped to other nodes. Nodes in the fine mesh will get mapped to nodes in the coarse mesh in order to receive the values (or vice versa).

The file (.def or .res) chosen as the run definition file will receive values from the source .res file. Note that if the run definition file had existing results (i.e. was a .res file), the solver will also write the differences between the source and target values. This can be used for file comparison (although be careful to back up the res file before interpolating onto it).


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