47 lines
2.1 KiB
Plaintext
Executable File
47 lines
2.1 KiB
Plaintext
Executable File
.. _negative_aij :
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 _place_holder;
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> **_NEGATIVE_AIJ_**
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>
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>> This command tests all edges of all boundary faces for negative coupling
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coefficients.
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It adds three attributes to the mesh object: num_neg_coup_coeff, type=INT,
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length=scalar -number of negative coupling coefficients
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neg_coup_coeff, type=VDOUBLE, length=num_neg_coup_coeff - value of coupling
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coefficient
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ietet_aij, type=VINT, length=num_neg_coup_coeff,rank=vector -
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for each negative coupling coefficient, i: ietet_aij(1,i) contains the
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tetrahedron number which contributes the most negative portion to the coupling
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coefficient, ietet_aij(2,i) contains the local face number that contains the
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local edge (ietet_aij(3,i)) which has the negative coupling coefficient These
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attributes can be used to generate a set of points to be added to the mesh in
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an attempt to reduce the number of negative coupling coefficients by the
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**refine** option. The points added are created by projecting the fourth node
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of the tetrahedron onto the identified face and then projecting this
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projection onto the identified edge. If the final projected point lies between
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the end points of the identified edge, this edge is refined. The
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identification and refinement steps may be iterated up to maxiter times.
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Alternatively the attribute may be used to create an **eltset **of the
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identified elements.
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The **rivara** option uses a rivara refinement method to add nodes on exterior
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boundary edges until all coupling coefficients are positive or until a maximum
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number of iterations has been exceeded. FORMAT: **negative_aij**
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**negative_aij**/**refine**
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**negative_aij**/**refine**/maxiter
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**negative_aij/eltset/**eltset_name
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**negative_aij/rivara** EXAMPLES: **negative_aij**
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**negative_aij/refine **only one iteration will be performed
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**negative_aij/refine/5** a maximum of 5 iterations will be performed
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**negative_aij**/**eltset**/bad_tets an element set called bad_tets will be made no refinement will be performed/ **negative_aij/rivara**
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**** _place_holder; [Click here for demos](../demos/refine_rivara/test/html/main_rivara.html)
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