MATLAB: Error using the polyder

convMATLABpolyder

Hello, I am using the version Matlab 2019a and aparently there is a bug using the polyder function. Even when I am trying to run the same calculations as in the example provided online, I get the following message:

>> p = [3 0 -2 0 1 5];

>> q = polyder(p)

Error using conv (line 10)

Dimensions have to be equal or larger than dimensions of the kernel!

Error in polyder (line 24)

a1 = conv(up,v); a2 = conv(u,vp);

Best Answer

You've likely written or downloaded a conv.m that's taking precedence over the conv function included in MATLAB. Line 10 of the conv function included in MATLAB is roughly in the middle of the help text, not an executable instruction.

To check this, run:

which -all conv

If there are any conv.m functions that are outside the matlabroot directory, rename or remove them.

Related Solutions

MATLAB: Differentiation question using diff and polyder

Problems like this are in a sense a bit artful because you have options. I suggest:

% % Part A:

Don't you actually want to calculate:

df1 = diff(y);

instead?

In that situation, I suggest perhaps plotting df1 as:

plot(x(1:length(df1)), df1)

% % Part B:

If you want to calculate a 3rd order polynomial fit, I suggest:

df2 = polyfit(x,y,3);

You might also find the polyval function helpful.

MATLAB: Conv() not working

I'm guessing you have written your own script conv.m that's taking precedence over the built-in conv function. To check this run:

which -all conv

If my guess is correct, rename or remove your conv.m script.

Best Answer

Related Solutions

MATLAB: Differentiation question using diff and polyder

MATLAB: Conv() not working

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