Approximate three-dimensional function using specified lookup method

**Library:**Simscape / Foundation Library / Physical Signals / Lookup Tables

The PS Lookup Table (3D) block computes an approximation to some
function `f=f(x1,x2,x3)`

given the `x1`

,
`x2`

, `x3`

, `f`

data points. The
three inputs and the output are physical signals.

You define the lookup table by specifying the **Table grid vector 1**
parameter (vector of data points along the first axis), the **Table grid vector
2** parameter (vector of data points along the second axis), the
**Table grid vector 3** parameter (vector of data points along the
third axis), and the **3D array of table values** parameter (array of
output values).

The `x1`

, `x2`

, and `x3`

data
vectors must be strictly monotonic, either increasing or decreasing. The array size of
the tabulated function values must match the dimensions defined by the input vectors.
That is, if the three input vectors have sizes 1-by-`m`

,
1-by-`n`

, and 1-by-`p`

, respectively, supply an
`m`

-by-`n`

-by-`p`

array of output
values.

The block generates output based on the input grid lookup using the selected interpolation and extrapolation methods. You have a choice of two interpolation methods and two extrapolation methods. You also have an option for the block to issue an error if any of the input signal values is outside the respective table grid vector range.