Documentation

# getData

Get current values of tunable-surface coefficients

## Description

Kco = getData(K) extracts the current value of a tunable surface. K is a tunableSurface object that represents the parametric gain surface:

$K\left(n\left(\sigma \right)\right)=\gamma \left[{K}_{0}+{K}_{1}{F}_{1}\left(n\left(\sigma \right)\right)+\dots +{K}_{M}{F}_{M}\left(n\left(\sigma \right)\right)\right],$

where:

• σ is a vector of scheduling variables.

• n(σ) is a normalization function (see the Normalization property of tunableSurface).

• γ is a scaling factor (see the Normalization property of tunableSurface).

• F1,...,FM are basis functions.

• K0,...,KM are tunable coefficients.

getData evaluates K at the current values of the coefficients K0,...,KM.

KcoJ = getData(K,J) extracts the current value of the coefficient of the Jth basis function FJ. Use J = 0 to get the constant coefficient K0.

## Input Arguments

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Gain surface, specified as a tunableSurface object,

Index of basis function, specified as a nonnegative integer. To extract the constant coefficient K0, use J = 0.

## Output Arguments

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Current coefficient values of the tunable surface, returned as an array.

If the tunable surface K is a scalar-valued gain, then the length of K is (M+1), where M is the number of basis functions in the parameterization. For example, if K represents the tunable gain surface:

$K\left(\alpha ,V\right)={K}_{0}+{K}_{1}\alpha +{K}_{2}V+{K}_{3}\alpha V,$

then Kco is the 1-by-4 vector [K0,K1,K2,K3].

For array-valued gains, each coefficient expands to the I/O dimensions of the gain. These expanded coefficients are concatenated horizontally in Kco. (See tunableSurface.) For example, for a two-input, two-output gain surface, Kco has dimensions [2,2(M+1)].

Coefficient of the Jth basis function in the tunable surface parameterization, returned as a scalar or an array.

If the tunable surface K is a scalar-valued gain, then KcoJ is a scalar. If K is an array-valued gain, then KcoJ is an array that matches the I/O dimensions of the gain.