esys-escript

specify different coefficients for different quadrature points

Asked by ceguo

Hi escript-developers/users,

I've another question. Can I specify quadrature points used in the mesh? Because in my case, the coefficients (tangent module etc.) are not evaluated by constitutive equation but by direct extracting from other simulation using other package (like DEM esys-particle). Each quadrature point is attached with such a DEM simulation. So how can I transfer the information (e.g. tangent module) obtained from DEM to the quadrature scheme in escript?

Best regards!
Ning

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Lutz Gross
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Lutz Gross (l-gross) said : 		#1

Can you make a statement on the ratio of particle to element size?

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ceguo (hhh-guo) said : 		#2

The DEM packing represents a RVE (representative volume element attached to one Gauss point) which is very small compared with the element, say, only contains hundreds or thousands of sand particles. I want to have FEM in the upscale, while DEM in the lower-scale which will transfer coefficients to the upscale in a hierarchical way. These two schemes don't interact in a parallel way.

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Best Lutz Gross (l-gross) said : 		#3

here comes a way you can do this (hope I understand your plan):

    # sets out point-by-point from the python level:
    out=Scalar(0.,in.getFunctionSpace())
    for i in xrange(in.getNumDataPoints()):
          in_loc = in.getValueOfDataPointAsTuple(i)
          out_loc = <everything you want to do with in_loc >
          out.setValueOfDataPoint(i, out_loc)

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ceguo (hhh-guo) said : 		#4

Thanks Lutz Gross, that solved my question.