What methods are utilized to interpolate and extrapolate data in the From Workspace block in Simulink 6.0 (R14)?

I am attempting to determine how the From Workspace block in Simulink 6.0 (R14) interpolates and extrapolates data; however, the information I seek is not available in the documentation accessed by typing the following at the MATLAB prompt:

doc fromworkspace

Answer 1

[MathWorks Support Team]

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

We have verified that information regarding the interpolation and extrapolation methods used by the From Workspace block is missing in the Simulink documentation.

The From Workspace block implements Lagrangian interpolation and extrapolation, which is a linear method. In the case of extrapolation, the last two data points are utilized in the computation.

Additional operations are executed in the case of certain data types. For example, if the data is of type integer (i.e., signed or unsigned), then interpolation is followed by truncation (if the interpolation result is out of range) and rounding.