Legend and Colors for Iteration function

2020 9 14
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更新时间：2020 9 15
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Good Day;
I need the steps that I can add Legend to my iteration function, where there are four curves, therefore, for each curve there must have specific color and legend that point to it.
Many Thanks

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Adam Danz
Adam Danz 2020-9-14
编辑：Adam Danz 2020-9-14

0 个投票

Use the displayname property to assign the legend string and use the "color" property to set the line color.
% Define colors
n = 12;
colors = jet(n);
% Plot within loop
hold on % Important!
for i = 1:n
plot(1:5, rand(1,5), '-', 'Color', colors(i,:),...
'DisplayName', sprintf('Line #%d',i));
end
legend()

14 个评论
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A.J.M
A.J.M 2020-9-14
Dear Mr.Adam Danz ;
the result as shown in the figure, and my code as shown below, where is my mistake please.
n = 4;
colors = jet(n);
hold on
figure(1)
for i=1:length(Rytov_var)
for j=1:length(Hp)
plot(Z, PDF_Hp, '-', 'Color', colors(i,:),...
'DisplayName', sprintf('Line #%d',i));
end
end
grid on
legend('σ^2_I=0.1','σ^2_I=0.2','σ^2_I=0.5','σ^2_I=0.8')
Adam Danz
Adam Danz 2020-9-14
编辑：Adam Danz 2020-9-14
  1. Use numel() instead of length().
  2. See the 4 "% <------changed" comments
  3. Am I correct that the i-loop controls the color and the j-loop controls the legend string? Where are those values (=0.1, =0.2, etc) coming from? If those are variable values, use those variable to assign the numbers rather than hard-coding them. There's no sense in using DisplayName and defining the legend strings in legend().
n = numel(Rytov_var); % <------changed
colors = jet(n);
hold on
figure(1)
for i=1:n % <------changed
for j=1:numel(Hp) % <------changed
plot(Z, PDF_Hp, '-', 'Color', colors(i,:),...
'DisplayName', sprintf('σ^2_I=%.1f',i)); % ?????????
end
end
grid on
legend()% <------changed
A.J.M
A.J.M 2020-9-14
编辑：A.J.M 2020-9-14
Mr. Adam Danz;
Where are those values (=0.1, =0.2, etc) coming from? Yes these value are varibles,and it belong to Rytov_var varible. I assigned it but the same result.
Adam Danz
Adam Danz 2020-9-14
Ok, then
plot(Z, PDF_Hp, '-', 'Color', colors(i,:),...
'DisplayName', sprintf('σ^2_I=%.1f',Rytov_var(i)));
% ^^^^^^^^^^^^
but that will result in duplicate colors and legend strings. Since I don't know what the two loops are supposed to do, I cannot suggest an alternative. Perhaps the 1st loop controls the legend string and the 2nd loop controls the color? If so,
n = numel(Hp);
colors = jet(n);
hold on
figure(1)
for i=1:numel(Rytov_var)
for j=1:n
plot(Z, PDF_Hp, '-', 'Color', colors(j,:),...
'DisplayName', sprintf('σ^2_I=%.1f',Rytov_var(i)));
end
end
grid on
legend()
A.J.M
A.J.M 2020-9-14
编辑：Adam Danz 2020-9-14
Mr. Adam Danz;
I'm sorry if I disturb you. The result as shown in the figure. Below is the original function that I want to plot it. The plot between PDF_Hp and the distance Z. I appreciate your efforts.
Z=100:250:5000; %Distance Between The Transmitter and Reciever in m
Rytov_var=[0.1,0.2,0.5,0.8];
for i=1:length(Rytov_var)
for j=1:length(Hp)
A1(i,j)=1./(Hp(j).*sqrt(2*pi*Rytov_var(i)));
A2(i,j)=((log(Hp(j))+0.5.*Rytov_var(i)).^2)./2.*Rytov_var(i);
PDF_Hp(i,j)=A1(i,j).*exp(-(A2 (i,j)));
end
end
Adam Danz
Adam Danz 2020-9-14
Take a few moments to understand what your loops are doing. I don't know what they are supposed to do and I can't run the code since there are missing variable values (e.g. Hp).
If you understand how my solution assigns color and assigns the legend string, I think you'll figure out what needs changed in your code. But since I don't understand what the loops are for and how color is supposed to be assigned and how the legend string is supposed to be assigned, I can't propose a solution.
Adam Danz
Adam Danz 2020-9-14
No problem, I'd be glad to help further if needed.
A.J.M
A.J.M 2020-9-14
That's very kind of you Mr. Adam Danz.
Accept my respect
A.J.M
A.J.M 2020-9-15
Good day Mr. Adam Danz;
This is my code, I plotted without loop, the new problem is the legend colors don't match the curves.
Z=100:250:5000; %Distance Between The Transmitter and Reciever in m
pointing_Err_angle=1*10^-5; %Pointing Error Angle in mrad
lambda=1550e-9; %Wavelength in nm
wo=5*10^-2; %Beam Waist at Z=0 in m
Cn=sqrt(5e-15); %Refractive Index Structure Parameter
% --------------------Calculation Section------------------------------
k=2*pi/lambda; %The number of optical wave
po=(0.55*(Cn)^2*k^2*Z).^(-3/5); %The Coherence Length
E=(1+2*wo^2./po.^2);
wz=wo*(1+E.*((lambda.*Z)./(pi*wo^2)).^2).^(1/2); %The Beam Waist
r=Z*(pointing_Err_angle); %The Radial Displacement B
%----------------------------------------Calculate Hp-------------------
v=(sqrt(pi)*a)./(sqrt(2)*wz);
a0=(erf(v)).^2; %Maximal Fraction of Collected Power at r=0
Wzeq=sqrt(wz.^2*((sqrt(pi).*erf(v))/(2*v.*exp(-v.^2))));
Hp=a0.*exp((-2*r.^2)./((Wzeq).^2));
%--------------------------Intensity Distribution---------------
Rytov_var=[0.1,0.2,0.5,0.8]; %Log irradiance variance (Roytov variance)
for i=1:length(Rytov_var)
for j=1:5:length(Hp)
A1(i,j)=1./(Hp(j).*sqrt(2*pi*Rytov_var(i)));
A2(i,j)=((log(Hp(j))+0.5.*Rytov_var(i)).^2)./2.*Rytov_var(i).^2;
PDF_Hp(i,j)=A1(i,j).*exp(-(A2(i,j)));
end
end
%--------------------------Plot Section---------------------------------
z=1250:1250:5000; %Distance for Plot Purpose
figure(1)
semilogy(z,PDF_Hp,'LineWidth',4);
xlabel('The Distance Z')
ylabel('The Probability Density Function ')
title('The PDF of Hp Vs The Distance')
legend('σ^2_I=0.1','σ^2_I=0.2','σ^2_I=0.5','σ^2_I=0.8')
grid on
figure(2)
semilogy(Rytov_var,PDF_Hp,'LineWidth',3);
xlabel('Roytov variance')
ylabel('The Probability Density Function ')
title('The PDF of Hp Vs Rytove Variance')
legend('σ^2_I=0.1','σ^2_I=0.2','σ^2_I=0.5','σ^2_I=0.8')
grid on
Adam Danz
Adam Danz 2020-9-15
I cannot run the full code because "a" is not defined.
v=(sqrt(pi)*a)./(sqrt(2)*wz);
Error:
Unrecognized function or variable 'a'.
A.J.M
A.J.M 2020-9-15
Sorry for this mistake;
a=0.5e-2;
Adam Danz
Adam Danz 2020-9-15
I see the problem. Look at the values you're plotting.
semilogy(z,PDF_Hp,'LineWidth',4);
PDF_Hp =
Columns 1 through 12
59.204 0 0 0 0 74.572 0 0 0 0 130.59 0
33.684 0 0 0 0 41.243 0 0 0 0 66.92 0
5.2821 0 0 0 0 5.3479 0 0 0 0 5.1881 0
0.42448 0 0 0 0 0.30818 0 0 0 0 0.12088 0
Columns 13 through 16
0 0 0 242.89
0 0 0 112.93
0 0 0 4.5326
0 0 0 0.032869
A line is created for each column so your plot actually has 16 lines, not 4.
The reason they don't appear is because in a log plot, 0 is not defined. However, those line objects are still produced - they are just not shown. As evidence of that, check out the 16 object handles.
h = semilogy(z,PDF_Hp,'LineWidth',4)
% h =
% 16×1 Line array:
%
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
% Line
The reason the "wrong" colors are defined is because you're only asking for the first 4 objects to appear in the legend. But objects 2-3-4 are all non-visible lines.
legend('σ^2_I=0.1','σ^2_I=0.2','σ^2_I=0.5','σ^2_I=0.8')
Solution
Get rid of the columns with 0s in PDF_Hp
A.J.M
A.J.M 2020-9-15
Thanks a lot, Mr. Adam Danz, the problem was solved. I appreciate your hard efforts
Accept my respect.

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