Glossary

Exodus Database

Conceptual data model of the ExodusII database and affect.exodus module.

attributes

Optional floating point numbers that can be assigned to each and every entry in a Nodal, Set, or Block entity. Every entry in an entity must have the same number of attributes, but the attribute values vary among the entries. Attributes are accessed through the member functions of an entity, for example, Set.num_attributes(), Set.attribute_names(), Set.attribute(), and Set.attributes().

block

A association of entries with the same topology containing node connectivity information. For example, an element Block is an association of element entries and the nodes connected to each element.

blocks

A dictionary-like container of the Block instances of a certain EntityType in a Database. The dictionaries of different types of blocks are accessible through the following attributes: Database.edge_blocks, Database.face_blocks, or Database.element_blocks.

coordinates

A special field associated with the Nodal entity storing the spatial coordinates of every node entry in the Database.

database

File storage for a mesh data model, a Database contains all the mesh entities and their corresponding entries, and the temporal Field variables.

distribution factors

Optional floating point values associated with every entry and every Set of a certain type, if they exist. Distribution factors are typically used in the simulation as a multiplier on an external load. Distribution factors are accessed through Sets.num_distribution_factors_all(), Set.num_distribution_factors(), and Set.distribution_factors().

entity

An association of a subset of entries of a certain type (elements, faces, sides, edges, nodes). An entity is either the single Global or Nodal entity of the Database, or one of the possible multiple members of the Blocks, Sets, or Maps entities of the Database.

entity ID

An integer associated with each existing entity in the Database, the integer is unique to each entity of the same EntityType. The entity ID’s are used as the keys used to access the dictionary-like containers Blocks, Sets, and Maps.

entity Type

One of the values of the enum EntityType, including NODAL, NODE_SET, EDGE_BLOCK, EDGE_SET, FACE_BLOCK, FACE_SET, ELEM_BLOCK, ELEM_SET, SIDE_SET, ELEM_MAP, NODE_MAP, EDGE_MAP, FACE_MAP, GLOBAL, and COORDINATE.

entry

Entries are the fundamental building blocks of the grid or mesh of a database. Entries refer to nodes, edges, faces, and elements of the Database mesh. Entries are not represented by their own Python objects, entry IDs, but they correspond to the first index of the FieldArrays.

field

A name for an array of values and the name of components associated with entries. The Field names are used to access the FieldArray values stored in the Database. Each of the named components of a Field with values in a FieldArray are a scalar variable in the Database. A field is a grouping of ExodusII variable by common name prefix; the suffix of the variable name (whatever follows the last underscore ‘_’ in the name) becomes a component name of the field. See also field array.

field array

The actual scalar, vector and tensor values accessed in the Database by using a Field name and components. The FieldArray is a multidimensional array, with the first index corresponding to entries. It contains floating point values that vary in space (by entry index) and time (time step). Entities that may have field array values: global, nodal, blocks, and sets. For fields on blocks or sets, the field may or may not be active on all entities of that type; to find out use Block.is_field_active() or Set.is_field_active(). The values of the field array may be accessed on all entries at a single time step, for example see Nodal.field(); or on a range of entries at a time step, for example, Nodal.partial_field(); or on a single entry at all existing time steps, for example, Nodal.field_at_times().

global

A Global is a single top level Database entity maintaining the spatial dimension, the number of time steps, the sums of all the entries of various types in the mesh (elements, faces, nodes) referenced in other Database entities. It is accessed from the attribute Database.global.

information data

Info data is a list of optional supplementary text strings associated with a database. Typically this might be the input file from the simulation run that was executed to create the database results. Information data is accessed through Database.info

internal numbering

The internal numbering of node entries is in the range [0, Global.num_nodes()]. The internal numbering of elements is by total subsequent entries in the Block in Database.blocks() (of type EntityType.ELEMENT_BLOCK) and these are in the range [0, Global.num_elements()].

map

A Map is a container of entries with new integers representing a number other than that of the default internal numbering for that type of entry.

maps

A dictionary-like container of the Map instances of a certain EntityType in a Database. The dictionaries of different types of maps are accessible through the following attributes: Database.element_maps, Database.node_maps, Database.edge_maps, or Database.face_maps.

quality assurance records

QA data are optional text strings in the Database, storing a history of application codes that modified the Database file, including the application name, description, date and time. Quality assurance data is accessed through Database.qa_records

nodal

The single entity of a Database that stores nodal coordinates, nodal fields, and nodal attributes. The Nodal object is accessed from Database.nodal.

properties

Optional named integer variables associated with every entity of a certain type in the database. The types of entities that may have properties are: Block, Map, and Set entities. Property names are accessed through the member function of the collection of entities, for example, Blocks.property_names(). Property values are accessed through the member functions of an entity, for example, Block.property().

set

A Set entity is a container of a subset of the entries of a certain type (nodes, edges, faces, sides, elements) in the Database. There may be multiple sets of a certain type and they may intersect. Sets are usually used to apply boundary conditions to portions of the mesh, and sets may contain attributes, properties and distribution factors, and multiple variable.

sets

A dictionary-like container of the Set instances of a certain EntityType in a Database. The dictionaries of different types of sets are accessible through the following attributes: Database.node_sets, Database.edge_sets, Database.face_sets, or Database.side_sets. Entries of side sets are actually the pairing of an element and a local side number.

variable

Variables, in a Database are named scalar floating point arrays. The values of variables vary in time and are associated with entries in the database. A single variable is one component of a more useful multi-dimensional FieldArray, there is often no need to refer to variables separately from a FieldArray. The suffix of a name of a Exodus variable is also the name of a Field component. The underlying scalar variable values making up field array may be accessed in the database in a similar way to their FieldArray counterpart.

time step

The discrete values of time at which the values of fields (variables) are stored in the database. The values of time steps are accessible through the attribute Database.globals.num_times and Database.globals.times.