Evaluate variable tuning goal at specified design point

When tuning controllers for multiple operating conditions, `varyingGoal`

lets
you adjust the tuning objectives as a function of the design point.
Use `getGoal`

to evaluate a variable goal at a
particular design point or for particular values of the sampling variables.

`TG = getGoal(VG,'index',k)`

`TG = getGoal(VG,'index',k1,k2,...)`

`TG = getGoal(VG,'value',x1,x2,...)`

returns
the effective tuning goal at the `TG`

= getGoal(`VG`

,'index',`k`

)`k`

th design point.
The absolute index `k`

is relative to the arrays
of parameter values in the `Parameters`

property
of the varying goal `VG`

. If you have specified `VG.SamplingGrid`

,
then `k`

is relative to the grid of design points
in that property.

returns
the effective tuning goal at the design point with coordinates `TG`

= getGoal(`VG`

,'index',`k`

1,`k`

2,...)`(k1,k2,...)`

.
These coordinates are indices into the multidimensional arrays in `VG.Parameters`

and `VG.SamplingGrid`

.
This syntax is useful when your design grid includes multiple scheduling
variables.

returns
the effective tuning goal at the design point whose scheduling-variable
values are `TG`

= getGoal(`VG`

,'value',`x`

1,`x`

2,...)`(x1,x2,...)`

. Use this syntax only if
you have specified design points in `VG.SamplingGrid`

.
For example, if `VG.SamplingGrid`

specifies a grid
of design points `(a,b)`

, then `TG = getGoal(VG,'value',-1,3)`

returns
the tuning goal at the design point `(a,b)`

= `(-1,3)`

.
If `(x1,x2,...)`

does not match any point in `VG.SamplingGrid`

,
then `getGoal`

returns the nearest point, in a
relative sense.