# Adding an outer for loop for a plot

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Benjamin on 5 Mar 2019
Commented: Benjamin on 6 Mar 2019
I have the following code:
eta = 0.4;
eta_c = 0.6;
rpf = eta/eta_c;
count = 0;
for x = 1:0.01:1.5
count = count + 1;
z(count) = g(x,rpf);
end
x= 1:0.01:1.5;
plot(x,z,'-')
grid on;
It does what I want. My question though is, how can I do an outer loop to also loop over eta? What if I want to have different values of eta, but not in any incremental order (4.0, 4.2, 4.7) etc. and then plot them all on the same graph with a hold on or something? Anyone know how I can do this? Assume my function is correct that is called

Bob Thompson on 5 Mar 2019
eta = [5.4 6.7 5.2];
hold on
for i = 1:length(eta);
eta_c = 0.6;
rpf = eta(i)/eta_c;
count = 0;
for x = 1:0.01:1.5
count = count + 1;
z(count) = g(x,rpf);
end
plot([1:0.01:1.5],z,'-')
grid on;
end
You could have a very similar loop for eta_c if you want to vary those values as well.
I changed your plot x values because while defining x works for when you just have the one loop, it would be better not to keep changing the size and value within the outer loop. It shouldn't directly cause a problem, but better safe than sorry.
Benjamin on 6 Mar 2019
thanks it works!

per isakson on 5 Mar 2019
Edited: per isakson on 5 Mar 2019
This is may approach. (Don't change the code that works.)
function cssm( )
eta = [ 4.0, 4.2, 4.7 ];
for e = eta
cssm_( e )
hold on
end
end
function cssm_( eta )
eta_c = 0.6;
rpf = eta/eta_c;
count = 0;
for x = 1:0.01:1.5
count = count + 1;
z(count) = g(x,rpf);
end
x = 1:0.01:1.5;
plot(x,z,'-')
grid on;
end
function out = g( x, rpf )
out = x + rpf;
end
It works but the hold-part asks for improvement. Then refine the code if (and only if) it's needed.