COMSOL Multiphysics™

eleqc
Purpose
eleqc
Define coefficient form or general form equation contributions.
Syntax
Description
el.elem = 'eleqc'
el.g{ig} = geomnum
el.form = 'coefficient' | 'general'
el.eqvars = 'on' | 'off'
el.geomdim{ig}{edim}.ind{eldomgrp} = domainlist
el.geomdim{ig}{edim}.dim{idim} = dimvarname
el.geomdim{ig}{edim}.ea{eldomgrp} = eacoeff
el.geomdim{ig}{edim}.da{eldomgrp} = dacoeff
el.geomdim{ig}{edim}.c{eldomgrp} = ccoeff
el.geomdim{ig}{edim}.al{eldomgrp} = alcoeff
el.geomdim{ig}{edim}.ga{eldomgrp} = gacoeff
el.geomdim{ig}{edim}.be{eldomgrp} = becoeff
el.geomdim{ig}{edim}.a{eldomgrp} = acoeff
el.geomdim{ig}{edim}.f{eldomgrp} = fcoeff
el.geomdim{ig}{edim}.ipoints{eldomgrp}{idim} = ipind
The eleqc element adds equation contributions in coefficient form or general form
as specified by the el.form field. It also defines variables that evaluate to various
parts of the equations. These equation variables can be turned off using the eqvars
field.
For the syntax of the ind field, see elempty. The ea, da, c, al, ga, be, a, and f
coefficients have the same syntax as the corresponding fem.equ fields. See further
the section “Specifying a Model” in the COMSOL Multiphysics Scripting Guide.
In contrast to the standard syntax, the eleqc coefficients have the same names on
all dimensions. That is, the standard fem.bnd.g and fem.bnd.q fields correspond
to a geomdim{ig}{sdim-1}.f and a geomdim{ig}{sdim-1}.a, respectively.
The ipoints field differs from the gporder fields in the standard syntax (for
example, fem.equ.gporder) in that it always contains pattern indices instead of
orders (see elgpspec).
The COMSOL Multiphysics user interface generates an eleqc element for
geometries where the solution form is the coefficient or general form. When
assembling using the weak solution form (the default), equations are converted to
weak form and an eleqw element is generated instead.
Cautionary
Because of the naming convention for equation variables, at most one eleqc
element per geometry can have equvars set to on. Because the default eleqc
element has equation variables turned on, unless otherwise specified, it is proper
procedure to turn them off for any additional eleqc elements added in the
fem.elem field.
74 | CHAPTER 1: COMMAND REFERENCE