Hi everyone, how to use modalfit command to estimate modal vectors from a frf matrix?

2 次查看（过去 30 天）

显示更早的评论

Ayisha Nayyar 2018-9-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/420106-hi-everyone-how-to-use-modalfit-command-to-estimate-modal-vectors-from-a-frf-matrix

评论： Ayisha Nayyar 2018-9-24

Hi everyone, how to use modalfit command to estimate modal vectors from a frf matrix?

4 个评论
显示 2更早的评论隐藏 2更早的评论

Ayisha Nayyar 2018-9-22

I still feel difficulty in using this command .

Walter Roberson 2018-9-23

You have not posted your code or a copy of the error message.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Ayisha Nayyar 2018-9-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/420106-hi-everyone-how-to-use-modalfit-command-to-estimate-modal-vectors-from-a-frf-matrix#answer_337964

编辑：Walter Roberson 2018-9-23

在 MATLAB Online 中打开

sorry Walter,

here is my code, where, b1 is a FRF matrix of size 2500x21, where 2500 represents frequency range and 21 are the points on beam, on which response is collected by accelerometer.

CODE

function [fn,dr,ms]= modalfit(frf,f,fs,mnum,Name,value)
frf=b1;
f=1:2500;
fs=6400;
mnum=6;
[fn,dr,ms]=modalfit(frf,f,fs,mnum,'FitMethod','lsce');
end

error message:

mnum=6;
[fn,dr,ms]=modalfit(frf,f,fs,mnum,'FitMethod','lsce');
Undefined function or variable 'b1'.
Error in modalfit (line 2)
frf=b1;

5 个评论
显示 3更早的评论隐藏 3更早的评论

Walter Roberson 2018-9-23

编辑：Walter Roberson 2018-9-23

在 MATLAB Online 中打开

You wrote

frf=b1;

Where are you expecting that the value of b1 will be found?

Note that this code will call itself recursively until it hits about 500 levels and then will fail as MATLAB decides you are probably in an endless loop (which you are.) When you design recursive routines (routines that call themselves) it is crucial that before calling yourself again, that you have a test deciding whether you have reached a case you can solve directly without calling yourself again.

In other words...

You seem to be trying to define a routine named "modalfit" that will intercept MATLAB's "modalfit" routine and provide values for some of the parameters, and then call MATLAB's "modalfit". But you are not calling MATLAB's "modalfit": you are calling your own modalfit since you used the same name.

Do not try to define your own function to intercept a MATLAB function of the same name. You can define, for example,

function [fn,dr,ms] = modalfit_b(b1)
  frf=b1;
  f=1:2500;
  fs=6400;
  mnum=6;
  [fn,dr,ms] = modalfit(frf, f, fs, mnum, 'FitMethod', 'lsce');
end

as this routine does not call itself.

Walter Roberson 2018-9-23

在 MATLAB Online 中打开

I suspect that you are using

function [fn,dr,ms] = modalfit(b1)

instead of what I wrote,

function [fn,dr,ms] = modalfit_b(b1)

Ayisha Nayyar 2018-9-24

Thanks for your help Walter,even if i wrote: function [fn,dr,ms] = modalfit(b1)

There is error,i.e. function [fn,dr,ms] = modalfit(b1) | Error: Function definitions are not permitted in this context.

请先登录，再进行评论。

请先登录，再回答此问题。

类别

Signal Processing Audio Toolbox Audio Processing Algorithm Design

在 Help Center 和 File Exchange 中查找有关 Audio Processing Algorithm Design 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by

Hi everyone, how to use modalfit command to estimate modal vectors from a frf matrix?

4 个评论
显示 2更早的评论隐藏 2更早的评论

回答（1 个）

5 个评论
显示 3更早的评论隐藏 3更早的评论

另请参阅

类别

标签

Community Treasure Hunt

Hi everyone, how to use modalfit command to estimate modal vectors from a frf matrix?

4 个评论 显示 2更早的评论隐藏 2更早的评论

回答（1 个）

5 个评论 显示 3更早的评论隐藏 3更早的评论

另请参阅

类别

标签

Community Treasure Hunt

4 个评论
显示 2更早的评论隐藏 2更早的评论

5 个评论
显示 3更早的评论隐藏 3更早的评论