findopOptions

Options for finding operating points from specifications

Syntax

options = findopOptions

options = findopOptions(Name=Value)

Description

options = findopOptions returns the default operating point search options. You can modify these options using dot notation.

options = findopOptions(Name=Value) returns an option set with additional options specified by one or more name-value arguments. Use this option set to specify options for the findop command.

Examples

Create Option Set for Operating Point Search

Create an option set for operating point search that sets the optimizer type to gradient descent and suppresses the display output of findop.

option = findopOptions('OptimizerType','graddescent','DisplayReport','off');

Alternatively, use dot notation to set the values of options.

options = findopOptions;
options.OptimizerType = 'graddescent';
options.DisplayReport = 'off';

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: DisplayReport="off" suppresses the display of the operating point search report to the Command Window.

OptimizerType — Optimizer type used by the optimization algorithm

"graddescent-elim" (default) | "graddescent" | "graddescent-proj" | "lsqnonlin" | "lsqnonlin-proj" | "simplex"

Optimizer type used by the optimization algorithm, specified as one of these values:

• "graddescent-elim" — Enforce an equality constraint to force the time derivatives of states to be zero (dx/dt = 0, x(k+1) = x(k)) and output signals to be equal to their specified known values. The optimizer fixes the states, x, and inputs, u, that are marked as Known in an operating point specification, and optimizes the remaining variables.

• "graddescent" — Enforce an equality constraint to force the time derivatives of states to be zero (dx/dt = 0, x(k+1) = x(k)) and the output signals to be equal to their specified known values. The optimizer also minimizes the error between the states, x, and inputs, u, and their respective known values from an operating point specification. If there are not any inputs or states marked as Known, findop attempts to minimize the deviation between the initial guesses for x and u, and their trimmed values.

• "graddescent-proj" — In addition to "graddescent", enforce consistency of model initial conditions at each function evaluation. To specify whether constraints are hard or soft, use the ConstraintType option. This optimization method does not support analytical Jacobians.

• "lsqnonlin" — Fix the states, x, and inputs, u, marked as Known in an operating point specification, and optimize the remaining variables. The algorithm tries to minimize both the error in the time derivatives of the states (dx/dt = 0, x(k+1) = x(k)) and the error between the outputs and their specified known values.

• "lsqnonlin-proj" — In addition to "lsqnonlin", enforce consistency of model initial conditions at each function evaluation. This optimization method does not support analytical Jacobians.

• "simplex" — Use the same cost function as lsqnonlin with the direct search optimization routine found in fminsearch.

For more information about these optimization algorithms, see fmincon (Optimization Toolbox), lsqnonlin (Optimization Toolbox), and fminsearch.

Dependencies

This option is not supported for finding periodic operating points.

OptimizationOptions — Options for the optimization algorithm

structure

Options for the optimization algorithm, specified as a structure created using the optimset (Optimization Toolbox) function.

Dependencies

This option is not supported for finding periodic operating points.

DisplayReport — Flag indicating whether to display the operating summary report

"on" (default) | "off" | "iter"

Flag indicating whether to display the operating point summary report, specified as tone of these values:

• "on" — Display the operating point summary report in the MATLAB^® command window when running findop.

• "off" — Suppress display of the summary report.

• "iter" — Display an iterative update of the optimization progress.

AreParamsTunable — Flag indicating whether to recompile the model when varying parameter values

true (default) | false

Flag indicating whether to recompile the model when varying parameter values for trimming, specified as one of these values:

• true — Do not recompile the model when all varying parameters are tunable. If any varying parameters are not tunable, recompile the model for each parameter grid point, and issue a warning message.

• false — Recompile the model for each parameter grid point. Use this option when you vary the values of nontunable parameters.

Dependencies

This option is not supported for finding periodic operating points.

ConstraintType — Constraint types for "graddescent-proj"

structure

Constraint types for "graddescent-proj" optimizer algorithm, specified as a structure with these fields:

• dx — Type for constraints on state derivatives

• x — Type for constraints on state values

• y — Type for constraints on output values

Specify each constraint as one of these values:

• "hard" — Enforce the constraints to be zero.

• "soft" — Minimize the constraints.

All constraint types are "hard" by default.

Dependencies

This option is not supported for finding periodic operating points.

Output Arguments

options — Operating point search options

findopOptions objects

Operating point search options, returned as a findopOptions object.

Version History

Introduced in R2013b

R2017b: 'graddescent_elim' value of the Optimizer property is now 'graddescent-elim'

The 'graddescent_elim' value of the Optimizer property of a findopOptions object is now 'graddescent-elim'.

Update Code

To update your code, change the optimizer value from graddescent_elim to graddescent-elim. The following table shows the typical usage of this property value and how to update your code.

If your code has this form:	Use this code instead:
opt = findopOptions('Optimizer',... 'graddescent_elim');	opt = findopOptions('Optimizer',... 'graddescent-elim')
opt = findopOptions; opt.Optimizer = 'graddescent_elim';	opt = findopOptions; opt.Optimizer = 'graddescent-elim';