How to fix this error?

Question

Habib 2017-5-11

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回答： usha shree 2019-8-9

I tried to run below script but "The grid vectors do not define a grid of points that match the given values." error is appeared and it is related to

z1=interp2(T,x,Z,T1,x1);

So how I can fix it?

 L=5;
 c=1;
 n=100;
 dt=0.005;
 tf=5;
 h=L/n;
 l=dt*c/h;
 l2=l^2;
 M=l2*(diag(ones(n,1),1)+diag(ones(n,1),-1));
 x=linspace(0,L,n+1);
 f=x.*sin(4*pi*x/L);
 g=0*x;
 t=0;
 w=f;
 z=(1-l2)*f+f/2*M+dt*g;
 t=t+dt;
 Z=[];
 T=[];
 while t<tf
    u=2*(1-l2)*z+z*M-w;
    z=u;
    Z=[Z,z];
    T=[T,t];
    w=z;
    t=t+dt;
 end
 T1=linspace(0,tf,100);
 x1=linspace(0,L,100);
 z1=interp2(T,x,Z,T1,x1);
 surf(x1,T1,z1);
 axis([0 L 0 tf -5 5]);
 xlabel('position')
 ylabel('time')
 zlabel('temperetur')

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KSSV 2017-5-11

Read the documentation of interp2....and then call the function.

z1=interp2(T,x,Z,T1,x1);

In the above sizes of T,x,Z should be same but they are no tin your case; so the error.

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Answer 1

KL 2017-5-11

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编辑：KL 2017-5-11

在 MATLAB Online 中打开

Did you read interp2 documentation ?

In your code,

z1=interp2(T,x,Z,T1,x1);

T and x must be of the same size and similarly T1 und x1. Z must be a matrix containing length(x) rows and length(T) columns.

whos T x Z T1 x1
  Name      Size                 Bytes  Class     Attributes
    T         1x1000                8000  double              
    T1        1x100                  800  double              
    Z         1x101000            808000  double              
    x         1x101                  808  double              
    x1        1x100                  800  double

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Habib 2017-5-11

Thanks. Yes, that is right.

but how I can make them same size? I tried but I didn't understand how do it. Infact, I don't know how i can reduce the size of "Z" and "T" inside "while" loop. the size of "Z" is 1*101000.

KL 2017-5-11