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LaGriT/documentation/lagrit_manual/commands/lower_d.txt
2025-12-17 11:00:57 +08:00

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.. _lower_d:
&nbsp_place_holder;
> **_LOWER_D_**
>
>> This suite of commands creates and handles the lower dimension structures
associated with a mesh.&nbsp_place_holder; The existing mesh is labeled
'd0'.&nbsp_place_holder; The next lower dimension mesh 'd1' and so
on.&nbsp_place_holder; For an original 3D mesh, the d1 structures are the
surfaces (2D) separating material regions, the d2 structures are the lines
separating the d1 surfaces and the d3 structures are the nodes at the ends of
the d2 lines.
Several new attributes are created which belong the original mesh object:
&nbsp_place_holder;
>>
>> name
>> type
>> length
>>
>> d0_nnodes_topo
>>
>> &nbsp_place_holder;
>> VINT, nnodes
>>
>> &nbsp_place_holder;
>> 0 = interior
1 = surface node
2 = line node
3 = line end node
>>
>> d1_nnodes
>> INT, scalar
>> number of nodes in this structure
>>
>> d1_elements
>> INT, scalar
>> number of elements in this structure
>>
>> d1_nef_cmo
>> INT, scalar
>> number of facets/element in this structure
>>
>> d1_nee_cmo
>> INT, scalar
>> number of edges/element in this structure
>>
>> d1_nen_cmo
>> INT, scalar
>> number of nodes/element in this structure
>>
>> d1_jtet_cycle_max
>> INT, scalar
>> the longest jtet cycle in this structure
>>
>> d1_itettyp
>> VINT d1_elements
>> element type
>>
>> d1_itetclr
>> VINT d1_elements
>> element selection number
>>
>> d1_itet off
>> VINT d1_elements
>> offset to d1_itet
>>
>> d1_jtet off
>> VINT d1_elements
>> offset to d1_jtet
>>
>> d1_itet
>> VINT d1_elements xd1_neu_cmo
>> list of nodes for each element
>>
>> d1_jtet
>> VINT d1_elements xd1_nef_cmo
>> list of face neighbors
>>
>> d1_elm_d0
>> VINT d1_elements&nbsp_place_holder;
>> elements face # in original mesh that this element came from
>>
>> d2_nnodes
>> INT, scalar
>> number of nodes in this structure
>>
>> d2_elements
>> INT, scalar
>> number of elements in this structure
>>
>> d2_nef_cmo
>> INT, scalar
>> number of facets/element in this structure
>>
>> d2_nee_cmo
>> INT, scalar
>> number of edges/element in this structure
>>
>> d3_nen_cmo
>> INT, scalar
>> number of nodes/element in this structure
>>
>> d2_jtet_cycle_max
>> INT, scalar
>> the longest jtet cycle in this structure
>>
>> d2_itettyp
>> VINT d2_elements
>> element type
>>
>> d2_itetclr
>> VINT d2_elements
>> element material number
>>
>> d2_itet off
>> VINT d2_elements
>> offset to d2_itet
>>
>> d2_jtet off
>> VINT d2_elements
>> offset to d2_jtet
>>
>> d2_itet
>> VINT d2_elements xd2_neu_cmo
>> list of nodes for each element
>>
>> d2_jtet
>> VINT d2_elements xd2_nef_cmo
>> list of face neighbors&nbsp_place_holder;
>>
>> d2_elm_d1
>> VINT d2_elements
>> element & face that this element came from in next higher level structure
>>
>> d3_nnodes
>> INT, scalar
>> number of nodes in this structure
>>
>> lower_d_flag
>> INT, scalar
>> 0= no lower d structure exist
=1 lower_d structures exist and are valid
=2 lower_d structures not valid
>>
>> The above set of attributes are created if the original mesh is
3D.&nbsp_place_holder; If the original mesh is 2D then the d1 structures are
created, but the d2 structures are simply the d2_nnodes.&nbsp_place_holder; If
the original mesh is 1D, then only the d1_nnodes structure is created.
>>
>> At the time the lower_d structures are created color table attributes:
d0_clrtab, d0_nclrs, .. are also created.
>
> FORMAT:
>
>> **lower_d **/ **create**/ [cmo_name]
&nbsp_place_holder; create lower_d structures in mesh object
**lower_d** /** release**/ [cmo_name]
&nbsp_place_holder;release lower_d structures
**lower_d** / **extract**/ [cmo_name/cmo1/cmo2/cmo2]
&nbsp_place_holder;create lower_d structures into named mesh objects cmo1,
cmo2, cmo3.
**lower_d** /** filter**/ [cmo_name] /[iclr1 | itp | **imt **| **clr **] / value [ **and** | **or** | **new** ]
&nbsp_place_holder; these commands are advised for expert users only.
>
> EXAMPLES:
>
>> &nbsp_place_holder;