# How to get subscripts in the legend of a Nichols plot?

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Bill Tubbs on 28 Aug 2020
Commented: Adam Danz on 28 Aug 2020
How do I put subscripts in a Nichols plot legend?
This works fine in a normal plot:
figure
plot([0 1],[3 4]); hold on
plot([0 1],[4 5])
plot([0 1],[5 6])
legend('G_2', 'G^2', 'G^2_p')
saveas(gcf,'test1.png')
produces:
But:
figure
nichols(Gp); hold on
nichols(Gc1*Gp);
nichols(Gc2*Gp);
legend('G_2', 'G^2', 'G^2_p')
saveas(gcf,'test2.png')
produces:
I tried this:
figure
nichols(Gp); hold on
nichols(Gc1*Gp);
nichols(Gc2*Gp);
legend('$G_2$', '$G^2$', '$\hat{G}^2_{p}$','Interpreter','Latex')
Produces:
Maybe this is the same bug reported in this question in 2015: Subscripts in MATLAB Legends

Adam Danz on 28 Aug 2020
This is caused by an extra excape character added when the legend is initially created.
Details are explained by these two answers here.
As explained in that link, you can call the legend twice and the second time should fix the problem.
% Demo
H = tf([-4 48 -18 250 600],[1 30 282 525 60]);
nichols(H)
legend('G^2_p')
legend('G^2_p') % <-- intentionally called again
##### 2 CommentsShowHide 1 older comment
Adam Danz on 28 Aug 2020
Indeed. The surprises we find in the entrails for Matlab....

R2019b

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