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This question is linked to this one:

Octave rlocus: format ploles and zero

I am using the Octave command pzmap but the size of the markers of the poles and zeros by default are very hard to see on the computer screen. I have looked at the pzmap.m file and changed the line:

h = plot (pol_args{:}, zer_args{:});

to

h = plot (pol_args{:}, zer_args{:},"markersize", 20);

but there is no effect.

and putting the markersize parameter in an actual code is not valid:

num=[1 3];
den=[1 5 20 16 0];
sys=tf(num,den);
pzmap(sys,"markersize", 20) %not valid

Any suggestion?

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2 Answers 2

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1
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The line you edited in pzmap.m is almost correct. You need to provide a "markersize" option for both poles and zeros.

Original plot:

enter image description here

After changing line 116 of \share\octave\packages\control-3.1.0\pzmap.m

h = plot (pol_args{:}, "markersize", 10, zer_args{:}, "markersize", 10);

enter image description here

Edit: to modify linewidth:

h = plot (pol_args{:}, "markersize", 10, "linewidth", 5, zer_args{:}, "markersize", 10, "linewidth", 5);

enter image description here

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  • \$\begingroup\$ Great. Is there a way to make the markers appear bold i.e. by changing the line weight? \$\endgroup\$
    – user11206
    May 14, 2018 at 8:33
  • 1
    \$\begingroup\$ @user11206 Appended it to answer. Check the edit. \$\endgroup\$
    – Vicente Cunha
    May 14, 2018 at 19:30
  • \$\begingroup\$ Great! It works fine in Octave. \$\endgroup\$
    – user11206
    May 15, 2018 at 5:19
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Try the following code,

num=[1 3];
den=[1 5 20 16 0];
sys=tf(num,den);
pzmap(sys) h=pzmap(sys)

hh = findobj(gca,'type','line');
for jj=2:length(hh)
set(hh(jj),'MarkerSize',12,'MarkerEdgeColor','red','LineWidth',5);
end

source

And the result is,

enter image description here

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  • \$\begingroup\$ Great. Is it possible to make the markers more pronounced as in "bold". \$\endgroup\$
    – user11206
    May 10, 2018 at 9:44
  • \$\begingroup\$ With the command: set(h.allaxes.Children(1).Children, 'MarkerSize', 20), I am getting the error message: error: matrix cannot be indexed with . \$\endgroup\$
    – user11206
    May 10, 2018 at 9:48
  • \$\begingroup\$ @user11206 check the edited answer \$\endgroup\$
    – Hazem
    May 10, 2018 at 9:53
  • \$\begingroup\$ pzplot is not yet part of Octave. Are you testing the code in Matlab or Octave? \$\endgroup\$
    – user11206
    May 10, 2018 at 14:18
  • 1
    \$\begingroup\$ Done. Thank you for the suggestion. stackoverflow.com/questions/50285757/… \$\endgroup\$
    – user11206
    May 11, 2018 at 5:48

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