No graphs after plot command

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semiha
semiha 2015-2-15
评论： semiha 2015-2-15
Hello everybody; I have a question about plot command. When i run the script, there is no error message but empty figure has appeared. I couldn't solve this problem using gcf or noFigure = 1; figure(noFigure); command. What should i do to see the graph? Thanks for your help
  2 个评论
Geoff Hayes
Geoff Hayes 2015-2-15
Semiha - what is the script that you are using? What code is being used to plot something to the figure? Please provide more details.
Star Strider
Star Strider 2015-2-15
semiha’s ‘Answer’ moved here ...
a = 100;
m = 1000;
n = 1000;
h = a/m;
t1 = 100;
k = t1/n;
x = 0:h:a;
t = 0:k:t1;
D = -k;
w0 = zeros(1,m+1);
w = zeros(n+1, m+1);
A = zeros(m+1, m+1);
B = zeros(m+1, m+1);
for j = 1:m+1
w0(j) = (1-(5*(1-3*i))/((1+6*(x(j)^3))));
end
w(1,:) = w0;
for p=1:n
for j=1:m+1
A2 (j)= k*1*i;
A(j,j) = A2(j);
end
for j=1:m
A(j,j+1) = 1 - 1i*D*abs(w(p,j)).^2;
end
for j=1:m-1
A(j,j+2)=k*1*i;
end
A(m,m)=k*1*i;
A(m,1)= 1 - 1i*D*abs(w(p,j)).^2;
A(m,2)=k*1*i;
A(m-1,1)=k*1*i;
A(m-1,m)= 1 - 1i*D*abs(w(p,j)).^2;
A(m-1,m-1)=k*1*i;
r =(A)*w(p,1:m+1)';
w(p+1,1:m+1)=r';
end
plot3 ( x, t,(abs(w(n,:))) );

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回答（1 个）

emehmetcik
emehmetcik 2015-2-15
Your output variable "w" mostly consists of "nan" (not a number) values. Probably the result of zero divided by zero at some point.
Only the first few rows of "w" have no nan's.
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emehmetcik
emehmetcik 2015-2-15
I'm not quite sure what the code does. But the problem seems to be that some values grow exponentially.
My recommendation is that you should re-check your code. The following commands can be useful as well:
dbstop if naninf
This will automatically put a debug point when a nan or inf value is encountered while the code is being executed.
dbclear all % To clear all debug points
semiha
semiha 2015-2-15
yes you are right i used dbstop if naninf command, it seems that one line creates this situtation. ( A(j,j+1) = 1 - 1i*D*abs(w(p,j)).^2) i should use this line to get a correct answer, but i will try to change it. Thanks

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