Storing values from a for loop and plot

I need to store the data generated for "Signal" and "Noise" and plot "Signal_to_Noise_Fl" vs. "Signal" for all the iterations. (Ndet and NZ are coming from some random numbers generated from randn function)

I keep getting blank plots when I plot either inside or outside the loop. Any suggestion?

for i=1:Ndet %(Signal)

b = 1:NZ; %(Noise)

Signal_to_Noise_Fl=i./b

end

[Matt Gaidica]

You need to add the code where you're trying to plot the values.

[Chanaka Navarathna]

for i=1:Ndet %(Signal)

for b = 1:NZ %(Noise)

Signal_to_Noise_Fl=i./b;

plot(Signal_to_Noise_Fl)

end

end

this is what I did and it gives a blank plot

Answer 1

[Star Strider]

Plot with a marker, and use the hold function:

Ndet = 10;
NZ = 10;
hold all
for i=1:Ndet %(Signal)
    for b = 1:NZ %(Noise)
    Signal_to_Noise_Fl=i./b;
    plot(Signal_to_Noise_Fl, 'pg')
    end
end
hold off

[Chanaka Navarathna]

Thank you! I think it is working. Do you think it is reasonable to use it for following code?

N = 10000; 
E = 10000; 
C = 10*10^-6;
Q = 0.6; 
f = 1/100; 
l = 1;
Counting_Noise = 100; 
Ncount=N+randn(N,1)*100;

Ndet = 2.303*Ncount*Q*E*C*l*0.01; 
NZ=Counting_Noise+randn(Counting_Noise,1)*20;
hold all
for i=1:Ndet %(Signal)
    for b = 1:NZ %(Noise)
    Signal_to_Noise_Fl=i./b;
    plot(i, Signal_to_Noise_Fl,'pg')
    end
end
    hold off   

[Chanaka Navarathna]

I have expanded the code a littlebit to create two separate graphs. Again it gives me empty graphs or graphs with one data point.

subplot(2,1,1);
    plot(i, Signal_to_Noise_Fl, 'pg');
    xlabel('Signal');
    ylabel('SNR');
    subplot(2,1,2);
    plot(b, Signal_to_Noise_Fl, 'pg');
    xlabel('Noise');
    ylabel('SNR');
    end
end
    hold off

[Star Strider]

As always, my pleasure!

I do, although I am not certain what you want to do.

Here is another option:

N = 10000; 
E = 10000; 
C = 10*10^-6;
Q = 0.6; 
f = 1/100; 
l = 1;
Counting_Noise = 100; 
Ncount=N+randn(N,1)*100;
Ndet = 2.303*Ncount*Q*E*C*l*0.01; 
NZ=Counting_Noise+randn(Counting_Noise,1)*20;

for i=1:numel(Ndet) %(Signal)
    for b = 1:numel(NZ) %(Noise)
    Signal_to_Noise_Fl(i,b)=Ndet(i)./NZ(b);
    
    end
end

figure
plot(Signal_to_Noise_Fl','-g') 

Experiment to get the result that you want.

[Chanaka Navarathna]

What I am looking for is to plot

1)Signal_to_Noise_Fl vs. Signal

2)Signal_to_Noise_Fl vs. Noise

in two separate graphs.

The code you have suggested generates a graph for 100 different iterations of Signal_to_Noise_Fl calculation I guess. Isn't it? Sorry, I am a begginer and I probably might be asking ignorant questions.

[Star Strider]

Try this:

N = 10000; 
E = 10000; 
C = 10*10^-6;
Q = 0.6; 
f = 1/100; 
l = 1;
Counting_Noise = 100; 
Ncount=N+randn(N,1)*100;
Ndet = 2.303*Ncount*Q*E*C*l*0.01; 
NZ=Counting_Noise+randn(Counting_Noise,1)*20;

for i=1:numel(Ndet) %(Signal)
    for b = 1:numel(NZ) %(Noise)
    Signal_to_Noise_Fl(i,b)=Ndet(i)./NZ(b);
    
    end
end

figure
subplot(2,1,1)
plot(Ndet, Signal_to_Noise_Fl', '.g')
xlabel('Signal')
ylabel('Signal-to-Noise')
title('Signal-to-Noise vs. Signal')
subplot(2,1,2)
plot(NZ, Signal_to_Noise_Fl, '.g')
xlabel('Noise')
ylabel('Signal-to-Noise')
title('Signal-to-Noise vs. Noise')

[Chanaka Navarathna]

It gives me this error

"Error using plot

Vectors must be the same length."

[Star Strider]

It worked for me.

‘Signal_to_Noise’ is a (10000 x 100) double array, ‘Ndet’ (that you describe as ‘Signal’) is a (10000 x 1) double array, and ‘NZ’ (that you describe as ‘Noise’) is a (100 x 1) double array. They should all plot correctly as in my code, and they did for me (in R2018b).

I have no idea what the problem is.

The data I plotted with the code I posted:

[Chanaka Navarathna]

I am using version 2016. May be because of that. I will give it a try again.

Thank you.

If possible please help me for my other questions.