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Add extra information to nyquist plots by wueestry · Pull Request #997 · python-control/python-control

@wueestry

Adds the possibility to add the unit circle (to get gain crossover frequency), Ms-circle (sensitivity) and Mt-circle (complementary sensitivity) to nyquist plots similar to the approach taken in JuliaControl

image

@murrayrm

It would be nice to have unit tests, even if they call the code to get coverage (better would be to check to make sure the lines are in the right place).

If the system is discrete time, are these still the right circles to draw?

Any interaction with axis scaling? Eg, if all of the action is very near the origin, might this reset the axes in a way that makes it harder to see the Nyquist plot? If so, is there a better way to do that (eg, fix the axes and let the circle disappear at the edges of the axes)?

@coveralls

Coverage Status

coverage: 94.533% (+0.02%) from 94.518%
when pulling 10d2010 on wueestry:nyquist_improvements
into feeb56a on python-control:main.

@wueestry

It would be nice to have unit tests, even if they call the code to get coverage (better would be to check to make sure the lines are in the right place).

If the system is discrete time, are these still the right circles to draw?

Any interaction with axis scaling? Eg, if all of the action is very near the origin, might this reset the axes in a way that makes it harder to see the Nyquist plot? If so, is there a better way to do that (eg, fix the axes and let the circle disappear at the edges of the axes)?

This works as well for discrete systems. And tests have now been added.
Not sure yet if fixing the axis is the best idea, as it would result in issues when plotting a second system in the same plot afterwards

murrayrm

If 'True', displays the unit circle, to read gain crossover frequency.

mt_circles : array_like, optional
draws circles corresponding to the given magnitudes of sensitivity

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For consistency, start phrase with a capital letter and end in a period.

draws circles corresponding to the given magnitudes of sensitivity

ms_circles : array_like, optional
draws circles corresponding to the given magnitudes in complementary sensitivity

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For consistency, start phrase with a capital letter and end in a period.

@murrayrm murrayrm marked this pull request as ready for review

June 30, 2024 16:11

@murrayrm

I rebased this onto the current main branch and added the ability to set the line style for the circles using config.defaults.