Help Error using eig Input to EIG must not contain NaN or Inf

2017 7 9
1 个回答
更新时间：2023 10 18
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0 个投票

Error using eig
Input to EIG must not contain NaN or Inf.
Error in composite_twoshaft_spurgear (line 450)
w=sort(abs(imag(eig(EF))));
E=[o,-(MM1+MM2+MMd);(MM1+MM2+MMd),(CC1+CC2+CCB1+CCB2)+(Oma1*(GG1+GGd1)+Oma2*(GG2+GGd2))];
F=[(MM1+MM2+MMd),o;o,(KK1+KK2+KKB1+KKB2)];
EF=-inv(E)*F;
w=sort(abs(imag(eig(EF))));
ww(:,n)=w;
[C,D]=eig(EF);

7 个评论
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KSSV
KSSV 2017-7-9
To calculate eigenvalues of a given matrix, there must be no Nans or inf. Your matrix EF have Nan's . Check it.
Walter Roberson
Walter Roberson 2017-7-9
Use
EF =-E\F
However your matrix might simply not be invertible
Walter Roberson
Walter Roberson 2017-7-9
If your values have multiple inf, or if one contains inf and the other contst least one 0, or if your values for E are all 0, then you will get nan results. If your E is not invertible otherwise then I do not recall if you get inf or nan as the result.
Walter Roberson
Walter Roberson 2017-7-9
Note to respond, click on "Comment on this" not on Flag. Flag is for pointing out a problem to the moderators such as if you notice a spam message.
Cheng Xu Feng
Cheng Xu Feng 2017-7-9
I check my EF are 408x408 matrix but all of elemenets are Nan. I don't know how to slove? I have 6dof problem.
KSSV
KSSV 2017-7-9
So problem is with MM1 etc values. You have to show us the complete code to solve the problem.
Walter Roberson
Walter Roberson 2017-7-9
Please show the output of
rcond(E)
rank(E)
rank(F)
nnz(~isfinite(E))
nnz(~isfinite(F))

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回答（1 个）

Cheng Xu Feng
Cheng Xu Feng 2017-7-10

0 个投票

I already solve this problem. but ans are wrong.

2 个评论
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Walter Roberson
Walter Roberson 2017-7-10
How do you know they are wrong?
What is your current code? What are
rcond(E)
rank(E)
rank(F)
nnz(~isfinite(E))
nnz(~isfinite(F))
laiche zeghdi
laiche zeghdi 2023-10-18
i have same problem . can you help me
1) An error occurred while running the simulation and the simulation was terminated
Caused by: Input to EIG must not contain NaN or Inf.
2) Cannot create variable 'if' in workspace Caused by:
ASSIGNIN cannot assign to variables with the same name as a MATLAB keyword

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