# 3.3.3.104. NXgraph_node_set¶

**Status**:

base class, extends NXobject

**Description**:

A set of nodes/vertices in space representing members of a graph.

**Symbols**:

The symbols used in the schema to specify e.g. dimensions of arrays.

d: The dimensionality of the graph. Eventually use one for categorical.

c: The cardinality of the set, i.e. the number of nodes/vertices of the graph.

**Groups cited**:none

**Structure**:

dimensionality: (optional) NX_POSINT {units=NX_UNITLESS}

cardinality: (optional) NX_POSINT {units=NX_UNITLESS}

identifier_offset: (optional) NX_INT {units=NX_UNITLESS}## Integer which specifies the first index to be used for distinguishing ...

Integer which specifies the first index to be used for distinguishing nodes. Identifiers are defined either implicitly or explicitly. For implicit indexing the identifiers are defined on the interval [identifier_offset, identifier_offset+c-1]. For explicit indexing the identifier array has to be defined.

The identifier_offset field can for example be used to communicate if the identifiers are expected to start from 1 (referred to as Fortran-/Matlab-) or from 0 (referred to as C-, Python-style index notation) respectively.

identifier: (optional) NX_INT (Rank: 1, Dimensions: [c]) {units=NX_UNITLESS}Integer used to distinguish nodes for explicit indexing.

is_a: (optional) NX_CHAR (Rank: 1, Dimensions: [c])## A human-readable qualifier which type or e.g. class instance the ...

A human-readable qualifier which type or e.g. class instance the node is an instance of. As e.g. a NeXus application definition is a graph, more specifically a hierarchical directed labelled property graph, instances which are groups like NXgraph_node_set could have an is_a qualifier reading NXgraph_node_set.

label: (optional) NX_CHAR (Rank: 1, Dimensions: [c])A human-readable label/caption/tag of the graph.

## Hypertext Anchors¶

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.