ml_frobeniusplot
Frobenius plots of transfer functions.
Contents
Syntax
[w, mag, tf, info] = ml_frobeniusplot(sys1, ..., sysN) [w, mag, tf, info] = ml_frobeniusplot(sys1, ..., sysN, opts)
[w, mag, tf, info] = ml_frobeniusplot(sys, rom1, ..., romM) [w, mag, tf, info] = ml_frobeniusplot(sys, rom1, ..., romM, opts)
Description
This function can be used to compute and plot Frobenius values of transfer functions in given intervals. It can be used to compute/plot
||G1(jw)||_F, ..., ||GN(jw)||_F, ||G(jw) - H1(jw)||_F, ..., ||G(jw) - HM(jw)||_F, ||G(jw) - H1(jw)||_F / ||G(jw)||_F, ...,
where G1, ..., GN are the transfer functions of sys1, ..., sysN, G the transfer function of sys and H1, ..., HM the transfer functions of rom1, ..., romM.
Input
sys1, ..., sysN - structure or state-space objects, containing {!} standard/descriptor/second-order systems rom1, ..., romM - structure or state-space objects, containing {!} standard/descriptor/second-order systems * opts - structure, containing the following optional entries:
Parameter | Meaning |
AccuracyTol | nonnegative scalar, tolerance used for the accuracy of the adaptive sampling method default: 0.1 |
DiffMode | character array, determining type of plot
|
FreqRange | vector of length 2, exponents of the frequency range, in which should be sampled default: [-4, 4] |
FreqSample | vector or character array, determining the frequency points, where to sample
|
FreqUnit | character array, frequency unit of the sample points and the plot 'rad/sec' - frequency in radian per second
|
Info | {0, 1}, used to disable/enable display of sampling steps default: 0 |
InitPoints | positive integer >= 3 or vector of length >= 3, initial number of equally distributed sampling points or initial frequency vector for opts.FreqSample == 'adapt' default: 3 |
LineSpecs {!} | character array, determining the line specifications for the plots default: '-' |
MagScale | character array, determines scaling of the magnitude axis
|
MagUnit | character array, magnitude unit in the plot
|
MaxPoints | positive integer, maximum number of sampling points, if DiffMode == 'equal' total number of points default: 500 |
ShowPlot | {0, 1}, used to disable/enable showing of plots default: 1 |
Note: Arguments/Parameters marked with {!} may also be a cell array containing multiple arguments.
Output
- w - matrix of size (number samples) x (number systems), conatining the frequency sampling points
- mag - matrix of size (number samples) x (number systems), containing the Frobenius magnitude values
- tf - 4-D array of size p x m x (number samples) x (number systems), containing the transfer function values
- info - structure, containing the following information:
Entry | Meaning |
AbsErr | if opts.DiffMode == 'off' empty, otherwise matrix of size (number samples) x (number systems - 1), containing the computed absolute error values |
Accuracy | vector, containing the computed accuracy values during the adaptive sampling and initial zeros for non-adaptive sampling |
Npts | positive integer, number of plotted points |
RelErr | if opts.DiffMode == 'off' empty, otherwise matrix of size (number samples) x (number systems - 1), containing the computed relative error values |
See Also