Adding Datasets

Datasets are collections of plotted data points that can be extrapolated into an equation based on the piecewise linear makeup of the plot. Each plot consists of straight line segments whose vertices represent their end points. A curve is fitted to the segments of the plot and an expression is derived from the curve that best fits the segmented plot. The created expression is then used in a piecewise linear intrinsic function such as pwl, pwlx or pwl_periodic.

Linear interpolation is performed such that when X is out of range – lower side, first two points from the dataset are used to calculate the slope, then the Y value is calculated from the slope. When X is out of range – higher side, the last two points from the dataset are used to calculate the slope, then the Y value is calculated from the slope. When X is within the range, the nearest point from the left and the nearest point from right are used to calculate the slope, then the Y value is calculated from the slope.

You can add datasets at either the project level or the design level. They can be for various purposes, including to define frequency-dependent port impedances or frequency-dependent global variables, and boundary definitions.

Project-level datasets are used typically for defining various material properties at the project level (applicable to all designs in the project). Otherwise, project-level datasets are not supported for design-level assignment.

Note: The descriptions of the various controls and fields for working with datasets are also applicable to the BH Curve window when Specifying BH Curves for Nonlinear Relative Permeability.

Design-level datasets can be used in geometry entities like parts, coordinate systems, points, and planes. Design-level datasets do not work with equation-based surfaces or curves. Design-level datasets can be used directly with piecewise linear functions in expressions or indirectly through variables that can refer to the dataset.

Design-level datasets can be used in the following operations:

Creating or editing geometry – when a geometry uses a dataset directly, edit dataset invalidates the solution. When a geometry uses a variable that is defined by dataset, editing the dataset does not invalidate the solution.
Creating an Animation – based on a variable that can index in datasets.
Copying and Pasting Geometry – if a part refers to a design dataset, it will be pasted to destination design.

The following procedure describes how to add a dataset manually. You can also add datasets:

by importing data from an external file.
by using the SheetScan tool.

For a project-level dataset, click Project > Datasets. For a design-level dataset, click Maxwell 3D or Maxwell 2D > Design Datasets or RMxprt > Design Datasets.

The Datasets dialog box appears, listing any project or design-level datasets.
Click Add.

Note: If you are adding either a project-level or a design-level dataset, you will be presented with the option to add either a 1D Dataset or 3D Dataset. See Adding 3D Datasets for specifics on this type of dataset.

The Add Dataset window appears. It contains fields for the Dataset name, and a table for x and y coordinates. It contains a graphic display that draws a line for the coordinates you add. It also includes buttons for the following functions:

Swap X-Y Data – swaps the x- and y- coordinates and adjusts the graphical display.
Import Dataset – provides a way to import data sets from an external source. The format is a tab-separated points file. Clicking the button opens a file browser window.
Export Dataset – provides a way to export the current dataset to a tab-separated points file. Clicking the button opens a file browser window.
Add Row Above – adds a new row to the table above the selected row.
Add Row Below – adds a new row to the table below the selected row.
Append Row – opens a dialog that lets you specify a number of rows to add to the table.
Delete Row – deletes the selected row or rows.

Optionally, enter a name other than the default for the dataset in the Name box.

Note: Project-level datasets must begin with a dollar sign character ($). If you do not type one, it will be added for you.
Enter the x- and y- coordinates: Type the x- and y-coordinates for the first data point in the row labeled 1.Type the x- and y-coordinates for the remaining data points in the dataset using the same method.
After you type a point’s coordinates and move to the next row, the point is added to the plot, adjusting the display with each newly entered point.
Note:
- The x-coordinate values for successive data points must increase within ten significant digits.
- You can also use the Import Dataset button to import data coordinates. Doing so will overwrite any existing values in the Coordinates panel.
When you are finished entering the data point coordinates, click OK.
Click Done in the Datasets window.

The dataset plot is extrapolated into an expression that can be used in parametric analyses, boundary definitions, or assigned to a material property value.

You can now edit, remove, clone, or export the dataset. You can also change the plot display properties.

Adding Datasets

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