GlossaryΒΆ

AAN
Always, Auto, Never
Various features in VisIt support an Always, Auto, Never choice. A setting of Never means to never enable the the feature and a setting of Always means to always enable the feature. A setting of Auto, which is typically the default, means the allow VisIt to decide when it thinks it is best to enable or disable the feature.
Integral Curve
An integral curve is a curve that begins at a seed location and is tangent at every point in a vector field. It is computed by numerical integration of the seed location through the vector field.
Node
Point
Vertex
These terms refer to the corners or ends of mesh elements.
Pathlines
A path rendered by an integrator that uses the vector field that is in-step with the integrator, so that as the integrator steps through time, it uses data from the vector field at each new time step.
Node-centered
Point-centered
These terms refer to a piecewise-linear (one degree of freedom at each of mesh element corner) interpolation scheme used to define a variable on a mesh. VTK tends to use the point terminology whereas VisIt tends to use the node terminology.
Parallel task
Although developers are working to enhance VisIt to support a variety of fine-grained parallelism methods (e.g. MC or GPU) and although some portions of VisIt have supported multi-threaded processing for several years, in the currently available implementations, a parallel task is an MPI rank.
Streamlines
A path rendered by an integrator that uses the same vector field for the entire integration.
SIL
Subset Inclusion Lattice
A Subset Inclusion Lattice or SIL is a term used to describe the often complex, graph like relationships among a variety of subsets defined for a mesh. A SIL describes which subsets and categories of subsets are contained within other subsets and subset categories. The Subset Window is the part of VisIt GUI that displays the contents of a SIL and allows the user to browse subsets and subset categories and turn subsets (and trees of subsets) on and off in visualizations.
SR
SR mode
SR is an abbreviation for Scalable Rendering. This is a mode of operation where the VisIt engine performs scalable, parallel rendering and ships the final rendered image (e.g. pixels) to the viewer. This is in contrast to standard mode where the engine ships polygons to the viewer to be rendered there.
Zone
Cell
These terms refer to the the individual computational elements comprising a mesh.
Zone-centered
Cell-centered
These terms refer to a piecewise-constant (single degree of freedom for an entire zone) interpolation scheme used to define a field variable on a mesh. VTK tends to use the cell terminology whereas VisIt tends to use the zone terminology.