double in a "gain" function

clf; M = 2; num = ones(1,M)/M; [g,w] = gain(num,1); plot(w/pi,g);grid

can you fix this please. The double value of num will not process through the gain function and I don't know what to do. It says: Undefined function 'gain' for input arguments of type 'double'.

Answer 1

[Adam]

What is gain?

Type:

which gain

on the command line. If it doesn't point to a function file then you presumably need to add whatever it is to your path. The error message for that is always a little misleading and has nothing to do with 'double', that is just the default type for matlab arguments so it always says unknown for double if the function just doesn't exist on the path at all.

[Kyler]

It does exist

[Kyler]

I looked that up and tried that

[Kyler]

C:\Program Files\MATLAB\R2013a\toolbox\dsp\filterdesign\@mfilt\gain.m % mfilt method that comes back

[Adam]

In that case the error message is a mystery as that is the only reason I am aware of for that message.

[Kyler]

Well wtf haha

[Kyler]

When I open the gain.m function there is no function in there only a bunch of comments. What up with that

[Kyler]

Its in the DSP toolbox