ModalTruncationOptions
Description
This object contains model order reduction options of ordinary (nonsparse) linear
time-invariant models, and is contained in the Options
property of a
ModalTruncation
object R
created using reducespec
. To
configure these options, use dot notation, for example, R.Options.ModeOnly =
true
.
For the full workflow, see Task-Based Model Order Reduction Workflow.
Properties
ModeOnly
— Flag to only compute modes
false
or 0
(default) | true
or 1
Flag to only compute modes for the original system sys
, specified
as a numerical logical 0
(false
) or
1
(true
).
When
R.Options.ModeOnly
istrue
, the software computes only the pole locations, damping, and natural frequency of the poles, which correspond to theMode
,Damping
, andFrequency
properties ofR
, respectively.When
R.Options.ModeOnly
isfalse
, the software computes a full modal decomposition and populates all properties ofR
.
DCFrequency
— Frequency for evaluating DC contributions
0
(default) | nonnegative scalar
Frequency for evaluating and matching DC contributions, specified as a nonnegative scalar.
For models with integrators, you cannot evaluate modal contributions at DC since the DC gain is infinite. To evaluate modal contributions and match gains at a different frequency, set the property to a positive value. The default value of this property corresponds to the true DC value.
InputScaling
— Input scaling factors
[]
(default) | vector
Input scaling factors, specified as a vector of length Nu, where
Nu is the number of inputs in the original model
sys
.
Use this option to emphasize specific input channels in sys
. The
software evaluates the modal contributions for the scaled system.
This property affects only the normalized DC contribution
(R.DCGain
). For the input scaling factor
Du and output scaling factor
Dy, the normalized DC contribution of
Gk(s) in continuous
time is obtained as
In discrete time, the software uses the first time samples Gk(1) and G(1).
OutputScaling
— Output scaling factors
[]
(default) | vector
Output scaling factors, specified as a vector of length Ny, where
Ny is the number of outputs in the original model
sys
.
Use this option to emphasize specific output channels in sys
. The
software evaluates the modal contributions for the scaled system.
This property affects only the normalized DC contribution
(R.DCGain
). For the input scaling factor
Du and output scaling factor
Dy, the normalized DC contribution of
Gk(s) in continuous
time is obtained as
In discrete time, the software uses the first time samples Gk(1) and G(1).
SepTol
— Relative accuracy of modal decomposition
1e-12
(default) | scalar between 0 and 1
Relative accuracy of modal decomposition, specified as a scalar between 0 and 1.
This option limits the condition number of the block diagonalizing transformation to
roughly SepTol
/eps
. Increasing
SepTol
helps yield smaller modal components at the expense of
accuracy.
Version History
Introduced in R2023b
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