Miscellaneous terms
This file provides some entries for various keywords that are not
used as name pointers elsewhere for ambiguity, incredible obscurity,
or some other reason.
Alice
A keyword for a special purpose command not documented.
Area
As a keyword, area is a read-only attribute of a facet.
Area_fixed
An obsolete way of declaring the total area of the surface fixed in the
datafile. Synonym: fixed_area. The preferred way of doing this now is to define a fixed
named quantity in the datafile,
such as
quantity the_area fixed = 2.3 global_method facet_area
This permits all the named quantity features to be used.
Attribute
As a keyword, "attribute" is used in the
define command for element
extra attributes.
Bare
As a keyword, "bare" is a
vertex attribute or an
edge attribute set by
the user that tells the Evolver not to expect the vertex or edge to
be attached to a facet.
Body
A body is a three dimensional geometric
element.
As a command keyword, "body" is an element name in
element generators,
either as the main element type, or as a subelement of a facet.
Burchard
A keyword for a special purpose command not documented.
Color
As a keyword, "color" is an attribute of edges and facets.
For the permitted values, see colors.
Conducting_knot_energy
Datafile keyword that automatically creates an energy named quantity
using the method
knot_energy as a global method.
May be followed in the datafile with a modulus value.
Insulating_knot_energy
Datafile keyword that automatically creates an energy named quantity
using the method
uniform_knot_energy as a global method.
May be followed in the datafile with a modulus value.
Constraint
"Constraint" can be used in a
general sense,
but as a keyword it refers to
level set constraints.
"Constraint" and "constraints" are interchangeable.
Content
"Content" is used to mean volume (or area, in the string model)
in constraint integrals.
Convex
A keyword used in declaring a
constraint
in the datafile that causes
a gap energy to be included.
The idea is to prevent straight edges and facets from
short-cutting curved constraints with big gaps.
Density
A keyword referring either to the gravitational density of a body, or
to the surface tension of a facet, or to the linear tension of an edge.
In the latter two cases, "density" is synonymous with "tension".
Edge
In general, one of the basic geometric elements. As a keyword, it
is used in element generators.
Synonym: edges.
Efixed
Obsolete datafile attribute to make an edge fixed without fixing its endpoints.
Keyword retained just for compatibility with old dump files.
Eprint
Function that prints an expression and returns the value. Syntax: eprint expr.
Meant for debugging; probably an archaic leftover from when the command
language was not as developed. Example: print sum(facet, eprint area)
will print out all the facet areas and then the sum.
Facet
In general, one of the basic geometric elements. As a keyword, it
is used in element generators.
Synonym: facets.
Facetedge
In general, an internal data structure representing the incidence of an
edge and a facet. As a keyword, it
can used in element generators
in LIST commands. For gurus only.
Synonyms: facetedges, facet_edge, facet_edges.
Fixed
Attribute that can be applied to
vertices,
edges,
facets, or
named quantities.
Formula
Datafile keyword used in
level set constraints
to introduce the function formula. Synonym: function
Gauss_curvature
Datafile keyword that automatically creates an energy named quantity
using the method
gauss_curvature_integral
as a global method.
May be followed in the datafile with a modulus value.
Tolerance
As a keyword, "tolerance" refers to a
fixed quantity attribute,
Div_normal_curvature
Toggle to make sq_mean_curvature energy calculate the mean curvature
by the divergence of the normal vectors at the vertices of a facet.
Force_pos_def
Toggle. If this is on during YSMP factoring of Hessian and the Hessian
turns up indefinite, something will be added to the diagonal element
to make it positive definite. Left over from some experiment probably.
H_inverse_metric
Toggle. Replaces force by Laplacian of force. For doing motion
by Laplacian of mean curvature.
Modulus
A keyword that is an attribute of a
named quantity
or a method instance, which
is a multiplier for the calculated value.
Opacity
Facet attribute for transparency on some geomview systems.
Syntax: set facet opacity value where value
is between 0 and 1. Actually, this just sets a global variable
for all facets simultaneously. The value is passed to geomview in
the alpha slot of the color.
Parameter
Refers to either a
parametric boundary
parameter, or a user-defined variable.
Parameter_file
In the top section of the datafile, a variable can be initialized
with a set of values in a file with the syntax
PARAMETER name PARAMETER_FILE string
I forget exactly how it is all supposed to work.
Pressure
Usually means an attribute of
fixed-volume bodies or
fixed named
quantities that is actually the Lagrange multiplier for the constraint.
As body attribute in the datafile, establishes
fixed pressure for the
body.
Also used rarely in the top section of the datafile to establish the
ideal gas model.
Surface_energy
An obsolete way of including vector surface energy integrals in the
datafile. The present method is to use
a named quantity
with the facet_vector_integral
method.
Total
An obsolete syntax for the value of a named quantity (e.g. my_quant) is
"total my_quant". The present syntax is "my_quant.value".
Valence
An attribute of a vertex, which is the number of incident edges,
or an attribute of an edge, which is the number of incident facets,
or an attribute of a facet, which is the number of vertices.
Vertex
One of the basic geometric elements.
As a keyword, it is used
in element generators.
Utest
Runs a test to see if triangulation is Delaunay. Meant for higher
dimensions and simplex model.
Stability_test
Command to find largest eigenvalue of
mobility matrix. Don't really
recall what this was for.
Tag
An obsolete facet attribute, once used to associate an arbitrary
value with a facet. Now superseded by
extra attributes.
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