Sum of plots in for loop

Hi there,

I generated the attached plots in a for loop.

What I want eventually is to sum these plots to generate the black curve.

How can I go on about that?

Thank you for your help in advance,

Arthur

[KSSV]

Share your code....Add all curves...is it what you want?

[Arthur Moya]

Hi @KSSV,

Please see the code below.

%% %Partial Temporal Coherence curve 
WL = 0.0195 % Ang^-1
DeltaS = 36 % Ang
g = [0:0.01:3] % Ang^-1

Etr = exp(-0.5*pi^2*DeltaS*WL^2.*g.^4);
plot (g,Etr);
%% %Contrast Transfer Function
D= [150:12.5:200] %Ang
for i=1:length(D)
Cs = -12960 % Ang
Xr = 0.5*pi.*D(i)*WL.*g.^2 + 0.25*pi*Cs*WL^3.*g.^4;
Wv= sin(Xr).*Etr;

hold on
plot (g,Wv)
xlabel('g(Ang^{-1})','Fontsize',20)
ylabel('sin X', 'Fontsize',20)
legend ('E_{t}','20','40','60','80','Location','best','Fontsize',30)
line(xlim, [0,0], 'Color', 'k', 'LineWidth', 1)
end 

Answer 1

[Rob Robinson]

I don't think the black curve is the sum of all of these curves as the amplitude would be significantly higher than any of the one lines when they are so close to being in phase? I've given an example below for just two curves of how you could calculate the sum of the curves or alternatively the average or maximum. Hopefully one of those is what you are looking for.

c = 0:0.25:0.25;

x = linspace(1,10,100);

figure()
hold on
ySum = zeros(length(c),length(x));
for cVal = 1:length(c)
    legendName = sprintf('y=sin(x+%.2f)',c(cVal));
    y = sin(x+c(cVal)) ;
    ySum(cVal,:) = y; 
    plot(x,y,'DisplayName',legendName);
end
plot(x,mean(ySum),'DisplayName' ,'Average')
plot(x,sum(ySum),'DisplayName' ,'Sum')
plot(x,max(ySum),'DisplayName' ,'Max')

legend('location','best')

[Arthur Moya]

Hi Rob,

I suspect the curve that most resembles what I am looking for is the max curve. I have seen below some suggestions that I may be looking for the envelope. What would be the difference between the max curve and the envelope?

Thank you and kind regards,

Arthur

Answer 2

[Ameer Hamza]

This seems like envelope(): https://www.mathworks.com/help/releases/R2020a/signal/ref/envelope.html of these curves. It is from the signal processing toolbox.

[madhan ravi]

xD was thinking the same !

[Arthur Moya]

Hi @Ameer Hamza and @madhan ravi,

I have looked at the envelope page. I may be doing something wrong, but it doesn't give me what I am actually looking for.

See attached image.

[Ameer Hamza]

Can you share the data?

[Arthur Moya]

Dear @ Ameer Hamza,

below is the code I used to generate the data.

Thank you and kind regards,

Arthur

%% %Partial Temporal Coherence curve 
WL = 0.0195 % Ang^-1
DeltaS = 36 % Ang
g = [0:0.01:3] % Ang^-1
Etr = exp(-0.5*pi^2*DeltaS*WL^2.*g.^4);
plot (g,Etr);
%% %Contrast Transfer Function
D= [150:12.5:200] %Ang
for i=1:length(D)
Cs = -12960 % Ang
Xr = 0.5*pi.*D(i)*WL.*g.^2 + 0.25*pi*Cs*WL^3.*g.^4;
Wv= sin(Xr).*Etr;
hold on
plot (g,Wv)
xlabel('g(Ang^{-1})','Fontsize',20)
ylabel('sin X', 'Fontsize',20)
legend ('E_{t}','20','40','60','80','Location','best','Fontsize',30)
line(xlim, [0,0], 'Color', 'k', 'LineWidth', 1)
end