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How to plot results from for loop as one line graph instead of separate results of each iteration?

Asked by catarina on 16 May 2013

Hello,

I would like to plot a graph which shows the results of a for loop that derived a matrix Y(20,1001). I would like all the results of the iterations of Y to be plotted as one continuous line graph instead of all the iterations separately. However my code plots a graph with several lines of different colour, which I'm assuming its plotting the result of each iteration separately in the same graph. Hope I'm explaining my self clearly. My loop is underneath. Any tips would be appreciated. Thanks.

 f=0:1000;
w=2*pi*f;
F=1;

%plate dimensions ad exciter location

Lx=0.286;

Lz=0.198;

x0=0.16;

z0=0.083;

%Plate data - Fibre board

h=3.25e-3 ; %thickness

E=1.4e9 ; %Young?s modulus

M=265*h; %Mass per unit area

mu=0.3; %Poisson?s ratio

eta=4e-2; %Damping Factor

p=265;

D=(E*(h^3))/(12*(1-mu)); %flexural rigidity

% calculate the eigenfrequencies and modes

i = 0;

for m = 1:5;

    for n = 1:5;
        if i<=19 
        i = i + 1;
        wmn(i)=(sqrt(D/(p*h)))*((((n*pi)/Lx)^2)+(((m*pi)/Lz)^2));  %modal 
angular frequency 
        mode(i,:) = [m n];
        end
    end
end

%sort the eigenfrequencies and the mode numbers

[wmn, I] = sort(wmn); wmn = wmn';

modesort(1:i,:)=mode(I,:);

T = [wmn, modesort];

i=0;

for q = 1:length(T(:,1))

        i=i+1;
        Y(i,:)=((4./(Lx.*Lz)).*(1./p))...
                .*(((sin((T(q,2).*pi.*x0)./Lx).*sin((T(q,3).*pi.*z0)./Lz))...
                .*(sin((T(q,2).*pi.*x0)./Lx).*sin((T(q,3).*pi.*z0)./Lz)))...
                ./((-w.^2)+(((T(q,1)).^2)*(1+(1j*(2*eta/(T(q,1))))))));
      figure(1)
      plot(f,20*log10(abs(Y)).')
end 

  2 Comments

There're many variables undefined in your code. And if the last PLOT function is outside of your for loop, it won't be the result of each iteration.

Hi Jing, I've added all the necessary variables now. Cant figure this out.

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3 Answers

Answer by Walter Roberson
on 16 May 2013

plot(f,(abs(Y)).')

  1 Comment

Hi Walter, I changed as you suggested but get the same results. I added the whole code to my question above.

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Answer by catarina on 16 May 2013

Hi Walter, I changed as you suggested but get the same results. I added the whole code to my question above.

  0 Comments

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Answer by Jing
on 17 May 2013

Hi Catarina, Y is a 20*1001 matrix! When you use plot, there'll be 20 lines for each row. If Y should be one line, you should not make it a 20*2001 matrix at first, or reshape it into a vector:

Y=Y';
Y=Y(:);

And you don't need to put PLOT into for loop if you don't want the plot of each iteration.

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