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Glossary

Items that are capitalized are Scala class names.

  • arity - The number of un-flattened DataTypes in the domain of a SampledFunction. This is equivalent to the number of arguments to a computational function. For example, a function with a domain of (x, y) and wavelength with a range of irradiance: "((x, y), wavelength) -> irradiance" has an arity of 2.
  • Dataset - A Dataset is more than just a set of Data. A Dataset is a cohesive collection of data and metadata. In Summary, a Dataset instance consists of three things:
    1. Global Metadata
    2. The functional data model representation of the dataset in the form of a DataType which includes variable metadata.
    3. The data in the form of a SampledFunction.
  • DataType - A recursive algebraic data type consisting of Scalars, Tuples, and Functions. The DataType is purely in the realm of the model. Since Tuples and Functions themselves contain multiple DataType objects they can be nested with arbitrary complexity, meaning a DataType can be represented as a tree.
    Also, every DataType must contain a Metadata object.
  • domain - The independent variables of a function.
  • fdml - (Functional Data Model Language) An xml file format to describe the contents of a Dataset.
    See the FDML Schema section below.
  • Function - A Function is a DataType consisting of exactly two DataType objects, a domain and a range. Function is a member of the DataType algebraic data type.
  • functional data model - A relational data model that specifies that relations are functions. Datsets consist of ordered sequences of samples that are decoupled from metadata. Operations that implement the functional algebra can be performed on these samples to create new datasets.
  • Metadata - An instance of Metadata is simply a list of key/value pairs to describe a DataType or Dataset. Every Scalar object is required to contain a Metadata object, but Metadata objects may be empty for Tuple and Function objects.
  • range - The dependent variables of a function.
  • Sample - A Sample is a lean representation of the data values in one sample of a SampledFunction. It is a Tuple2 (pair) of DomainData and RangeData which are type aliases for Array[Any]. The values can be scalar values or SampledFunctions (in the range).
  • SampledFunction - The data representation of a Dataset with the Function DataType. A SampledFunction can provide an fs2.Stream of Samples and be "evaluated" at a given domain value.
  • Scalar - A Scalar is a DataType consisting of a single atomic variable. A DataType of arbitrary complexity must ultimately consist of Scalar objects as the leaf nodes of the representation tree. Scalar is a member of the DataType algebraic data type.
  • Tuple - A Tuple is a DataType consisting of a list of DataType objects. Unlike a function, the Datatype objects in a Tuple are associated but are not dependent on each other.
    An example is a 2D point consisting of the x,y Tuple. The scalars x and y are associated but x is not a function of y nor is y a function of x. Elements of a Tuple also do not have to be of the same type. Tuple is a member of the DataType algebraic data type.