# Warning: Imaginary parts of complex X and/or Y arguments ignored.

3 views (last 30 days)
Shayla Merrigan on 19 Jun 2022
In the higlighted, underlined, bolded line there is an issue that I can't seem to figure out why it keeps saying "Warning: Imaginary parts of complex X and/or Y arguments ignored."
% 100 Gaussian Normal distributed random numbers
xi = 1 + 1.9*randn(100,1);
yi = 3 + rands(100,1);
% Parameters
param.P = 0.9; % 90% Error ellipse
param.option = 'Prob';
param.Dec = 200; %200 points of error ellipse
[a,b,amean,bmean] = ErrorEllipse2D(xi,yi,param);
figure('NumberTitle','off','Name','Error Ellipse');
plot(a,b,'Color','blue');
grid on;
hold on;
axis equal;
plot(xi,yi,'Marker','+','LineStyle','none');
plot(amean,bmean,'Marker','o','MarkerFaceColor','black','LineStyle','none','color','black');
title('Gaussian random numbers centered at [1,3]')
xlabel('x - numbers');
ylabel('y - numbers');
Walter Roberson on 19 Jun 2022
We do not have the code for ErrorEllipse2D

Sulaymon Eshkabilov on 19 Jun 2022
from your problem statement, your calculation results a, b and amean, bmean contain some complex values. Thus, plot() fcn plots only real parts of their values. If you want to plot real parts of a vs. b and amean vs. bmean, and imaginary of ab vs. b, and amean vs. bmean, that can be attained with the followings:
...
figure('NumberTitle','off','Name','Error Ellipse');
yyaxis left
plot(real(a),real(b),'Color','blue'); % Real part of a and b
yyaxis right
plot(imag(a),imag(b),'Color','red'); % Imag. part of a and b
grid on;
hold on;
axis equal;
yyaxis left
plot(xi,yi,'Marker','+','LineStyle','none');
plot(real(amean),real(bmean),'Marker','o','MarkerFaceColor','black','LineStyle','none','color','black');
ylabel('Real part of y - numbers');
yyaxis right
plot(imag(amean),imag(bmean),'Marker','*','MarkerFaceColor','red','LineStyle','none','color','red');
title('Gaussian random numbers centered at [1,3]')
xlabel('x - numbers');
ylabel('Imag. part of y - numbers');
% etc.

R2022a

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