Approximate one-dimensional function using specified lookup method
Physical Signals/Lookup Tables
The PS Lookup Table (1D) block computes an approximation
to some function
f=f(x) given data vectors
Both the input and the output are physical signals.
The length of the
vectors provided to this block must match. Also, the
vector must be strictly monotonic, either increasing or decreasing.
You define the lookup table by specifying the Table
grid vector parameter as a 1-by-
x data vector) and the Table values parameter
as a 1-by-
n vector (
f data vector).
The block generates output based on the input values 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 the input signal value
is outside the table grid vector range.
Specify the vector of input values as a one-dimensional array. The input values vector must be strictly monotonic, either increasing or decreasing. The values can be nonuniformly spaced. For smooth interpolation, the vector must contain at least three values. For linear interpolation, two values are sufficient.
Specify the vector of output values as a one-dimensional array. The output values vector must be of the same size as the input values vector.
Select one of the following interpolation methods for approximating the output value when the input value is between two consecutive grid points:
Linear — Uses a
linear function. Select this option to get the best performance.
Smooth — Uses a
modified Akima interpolation algorithm. For details, see
Select this option to produce a continuous curve with continuous first-order
Select one of the following extrapolation methods for determining the output value when the input value is outside the range specified in the argument list:
Linear — Extends
from the edge of the interpolation region linearly. The slope of the
linear extrapolation is equal to the slope of the interpolated curve
at the edge of the interpolation region.
Nearest — Extends
from the edge of the interpolation region as a constant. The value
of the nearest extrapolation is equal to the value of the interpolated
curve at the edge of the interpolation region. Select this option
to produce an extrapolation that does not go above the highest point
in the data or below the lowest point in the data.
Error — Issues an
error if the input signal is outside the range of the table. Select
this option to avoid going into the extrapolation mode when you want
your data to be within the table range.
The block has one physical signal input port and one physical signal output port.