Concepts and Terminology

Data containers

DPF sees fields of data, not physical results, making it a very versatile tool that can be used in a variety of ways across teams, projects, and simulations.

The data source is one or more files in which analysis results can be found.

A field is the main simulation data container. For transient/harmonic/modal or multi-step static analyses, a field container is used to hold a set of fields (one field for each time step, each frequency).

The physical entity with which the field is associated is called the support. For example, the support can be a mesh, geometrical entity, or time or frequency values.

In most cases you will not want to work with the entire set of data, but rather a subset of that data. To achieve this you define scoping. Scoping is a subset of the model’s support. Typically, scoping can represent node IDs, element IDs, time steps, frequencies, joints, and so on. Scoping describes a spatial and/or temporal subset on which the field is scoped.

In DPF, field data is always associated with its scoping and support, making the field a self-describing piece of data. For example, in a field of nodal displacement, the displacement is the simulation data and the associated nodes are the scoping. A field can also be defined by its dimensionality, unit of data, and location.

The location is the type of topology associated with the data container. DPF uses three different spatial locations for finite element data: Nodal, Elemental, and ElementalNodal. A Nodal location describes data computed on the nodes, while an Elemental location describes data computed on the element itself. These nodes and elements are identified by an ID — typically a node or element number. An ElementalNodal location describes data defined on the nodes of the elements, but you must use the Element ID to retrieve it. To achieve this you define Elemental scoping or Nodal scoping.

The meshed region is an entity describing a mesh. Node and element scopings, element types, connectivity (list of node indices composing each element) and node coordinates are the fundamental entities composing the meshed region.

Concepts summary

The following example summarizes the concepts above:

Data manipulation

Operators

Operators are the main objects used to create, transform and stream the data. An operator is composed of a “core” that handles the calculation, and input and output “pins” (think of an integrated circuit in electronics). These pins enable you to provide input data to each operator. When the operator is evaluated, it processes the input information to compute its output.

Input pins allow users to pass on their data to the operator. DPF data container types, standard types or operators' outputs can be connected on the input pins (connecting an operator output to another operator input doesn't evaluate this input operator). The inputs allow the user to choose the time/frequencies on which to evaluate a result, to specify the files where to find a result, to provide a field on which he wants an operation to be computed, ans so on. Optional input pins to customize even more the operator outputs.

Output pins allow to get the results of the operation. An Operator can have one or several outputs which are usually DPF data containers.

Configurations allow you to optionally choose how the operator will run. This is an advanced feature used for deep customization. The different options can change the way loops are done. It can also specify whether the operator will perform validity checks on the input or not.

Workflow

Operators can be chained together to create workflows. A workflow is a global entity that you use to evaluate the data produced by the operators. It needs input information and computes the requested output information.

Think of a workflow as a black box in which some operators are chained, computing the information for which it is made:

The following example shows operators that have been chained together to create a total deformation workflow:

This workflow can be used in any simulation workflow using any data source as input.