SparseZeroPoleTruncationOptions

Options for model order reduction with zero-pole truncation

Since R2025a

Description

This object contains model order reduction options of zero-pole truncation and is contained in the Options property of a SparseZeroPoleTruncation object R created using reducespec. To configure these options, use dot notation, for example, R.Options.Focus = [0,15].

Properties

UseParallel — Use parallel computing

0 or false (default) | 1 or true

Use parallel computing during zero-pole computation, specified as a numeric or logical 0 (false) or 1 (true).

When UseParallel is set to true, you can explicitly choose to scale to your preferred parallel environment. Enabling parallel computing may result in improved performance during zero-pole computation. However, even with UseParallel set to false, the algorithm can use built-in multithreading to make best use of the local resources. For more information, see MATLAB Multicore.

This option requires a Parallel Computing Toolbox™ license.

Focus — Frequency range of interest

[0 Inf] (default) | vector

Frequency range of interest, specified as a vector of form [0,fmax]. When you specify a frequency range of focus, the algorithm computes only the poles with natural frequency in this range. For discrete-time models, the software approximates the equivalent natural frequency through Tustin transform.

Since this method computes all poles and zeros in the specified frequency range, you typically specify a low-frequency range to limit computing a large number of poles and zeros. By default, the focus is unspecified ([0 Inf]) and the algorithm computes up to MaxNumber poles and zeros.

MaxNumber — Maximum number of poles and zeros to compute

1000 (default) | positive integer

Maximum number of poles and zeros to compute, specified as a positive integer. This value limits the number of poles and zeros computed by the algorithm and the order of the approximation of the original sparse model.

Shift — Spectral shift

0 (default) | finite scalar

Spectral shift, specified as a finite scalar.

The software computes poles with the natural frequency in the specified range [0,fmax] using inverse power iterations for A-sigma*E, which obtains eigenvalues closest to the shift sigma. When A is singular and sigma is zero, the algorithm fails as no inverse exists. Therefore, for sparse models with integral action (s = 0 or at z = 1 for discrete-time models), you can use this option to implicitly shift poles or zeros to the value closest to this shift value. Specify a shift value that is not equal to an existing pole or zero value of the original model.

Tolerance — Accuracy of computed poles

1e-12 (default) | positive finite scalar

Tolerance for accuracy of computed poles, specified as a positive finite scalar. This value controls the convergence of computed eigenvalues in inverse power iterations.

Display — Show or hide progress report

"on" (default) | "off"

Show or hide progress report, specified as either "off" or "on".

Version History

Introduced in R2025a