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Why is this wrong??

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Iris
Iris 2012-10-24
关闭： MATLAB Answer Bot 2021-8-20
Hello :) I'm trying to draw the plots for E=a*c when j = 1 and E = a*b when j assumes other values, all in the same figure. The program just draws the first one, for E=a*c, and I cant understand why because it computes all different E for all the j (computes but does not do the plot). Can you tell me what I'm doing wrong? Your help will be very appreciated! Thanks in advance!
hold on
for j = 1:i
tau = (12*v*t(j)*Myr)/ro^2;
I = besseli(0.25,2*x./tau);
a = (md/(2*pi*ro));
b = (tau^-1).*(x.^-1/4).*I.*exp(-(1+x.^2)/tau);
c = normpdf(x,1,0.05);
if j == 1
E = a.*c;
else
E = a.*b
end
plot(x, E.*(1/a), colors(j))
end
hold off
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Iris
Iris 2012-10-24
Ms = 1.98919e33;
Rs = 6.9599e10;
Myr = 3.15569e13;
v = 1e5;
md = 0.01*Ms;
ro = 2*Rs;
x = [0:0.016:16]
t = [0:2e12:1e13];
i = length(t);
colors = ['r' 'b' 'g' 'b' 'g' 'b' ];
for j = 1:i
tau = (12*v*t(j)*Myr)/ro^2;
I = besseli(0.25,2*x./tau);
a = (md/(2*pi*ro));
b = (tau^-1).*(x.^-1/4).*I.*exp(-(1+x.^2)/tau);
c = normpdf(x,1,0.05);
if j == 1
E = a.*c;
else
E = a.*b
end
hold on
plot(x, E.*(1/a), colors(j))
end
hold off
end
Christoph
Christoph 2012-10-24
Weird since it works for me (R2008a, V7.6.0). Have you checked the output using subplot(2,3,j) at the start of the loop? since the value of E peaks at "8" in the 1st and <10^-12 in the other plots, so all together they appear as line... Otherwise, which Matlab release do you use?

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回答（2 个）

Matt Fig
Matt Fig 2012-10-24
编辑：Matt Fig 2012-10-24
I run your code and it plots 6 lines. check for yourself:
>> length(findobj('type','line'))
ans =
6
I think maybe you are not noticing because some lines overlap. Have a look:
ylim([0 1e-12])
Matt J
Matt J 2012-10-24
Might be useful to change this
hold on
plot(x, E.*(1/a), colors(j))
to this
semilogy(x, E.*(1/a), colors(j));
hold on

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