Using addition on X–Y data objects

You can use addition on previously saved X–Y data objects to produce a new X–Y data object.

See Also
Understanding X–Y data interpolation and extrapolation
Summing two or more X–Y data objects
Appending two or more X–Y data objects
Combining two X–Y data objects
Using X–Y data operations

Context:

Use the mathematical + symbol to operate on a previously saved X–Y data object (a collection of ordered pairs) to produce a new X–Y data object. The + operator accepts two commutative arguments and can be applied in one of two ways:

To add a scalar to an X–Y data object:

This method yields a new X–Y data object having the same X-coordinate values as the original X–Y data object. Abaqus/CAE computes the new Y-coordinates as the scalar added to each original Y-coordinate. For example, if

XYData=[(1,1),(2,2),(3,3)],

then

(XYData + 5)=[(1,6),(2,7),(3,8)].
To add an X–Y data object to another X–Y data object:

This method yields a new X–Y data object having as its X-coordinates all X-coordinates of the first data object and any additional X-coordinates needed for alignment of the two objects. Abaqus/CAE computes additional X–Y data pairs by interpolation and extrapolation. The new data object has as its Y-coordinates the Y-coordinates of the first data object added to the Y-coordinates of the second data object. For example, let

XYData1=[(1,1),(2,2),(3,3)],

and

XYData2=[(4,4),(5,5)].

For alignment, Abaqus/CAE computes the values of the first and second data objects as:

XYData1 extrapolated=[(1,1),(2,2),(3,3),(4,3),(5,3)],

and

XYData2 extrapolated=[(1,4),(2,4),(3,4),(4,4),(5,5)];

then

(XYData1 + XYData2)=[(1,5),(2,6),(3,7),(4,7),(5,8)].

Figure 1 illustrates the above example.

Figure 1. X–Y plot illustrating addition of data objects.

Note:

This application of the + symbol has the same behavior as the sum function.

  1. Locate the Operate on XY Data dialog box.

    From the main menu bar, select ToolsXY DataCreate. Click Operate on XY data in the dialog box that appears; then click Continue. The Operate on XY Data dialog box appears.

  2. From the XY Data choices, click the name of the X–Y data object on which to operate and click Add to Expression. You can choose from all X–Y data objects previously saved within this session (listed alphabetically in the XY Data field).

    The X–Y data object name appears within the expression window.

  3. From the Operators listed, click +.

    The + symbol appears after the data object name in the expression window.

  4. To specify the second argument, do one of the following:

    • Use your mouse and keyboard to enter a scalar as the second argument of the + operator in the expression window, or

    • From the XY Data choices, click the name of a data object argument for the + operator in the expression window and click Add to Expression.

  5. To continue to build your expression, position the cursor in the expression window and type in or select the functions, operators, and X–Y data you want to include.
  6. To evaluate and display your expression, click Plot Expression.
  7. To save your new X–Y data object, click Save As and then provide a name in the dialog box that appears.

    Saving your data object makes it available for future operations within this session and for inclusion in X–Y plots containing multiple data objects.

  8. When you are finished, click Cancel to close the dialog box.