Function "finite.m" is missing for butter!

I don't understand why the Matlab "butter.m" function miss the function "finite.m" to work even if I've the signal treatment toolbox?

    >> [B,A] = butter(2,[0.2 0.5])
    Undefined function 'finite' for input arguments of type 'double'.

    Error in zp2ss (line 45)
    p = p(finite(p));

    Error in butter (line 87)
    [a,b,c,d] = zp2ss(z,p,k);

Thank you for your support

[Fitra Hidiyanto]

try isfinite() instead of finite(), you can see on link : http://prefrontal.org/blog/2009/04/matlab-finite-function-warnings/

Answer 1

[Andreas Goser]

This might happen in cases where there are multiple "finite" commands or variable names. Please use the "WHICH" command to identfy "finite" commands or variable names on the MATLAB path that cause this.

[Vinc]

Thank you Andreas for your answer. I tried but it seems that no 'finite' commands or variable exist on my version of Matlab.

>> which finite -ALL
'finite' not found.

Maybe if someone send me this function it would fix this issue.

Thank you.

[Andreas Goser]

I see. I do not believe this is necessary. Point is you use a different release than I do (R2013a on Win64) and in my zp2ss file, there is no call to finite at all.

My suggestion:

Open butter.m and zp2ss.m in the editor and use breapoints to debug the code. Then you will be able to see what happens in the function.