Re: inf values for mean(___) and sum(___) functions

On 04/27/2015 11:19 PM, Christoph Meier wrote:
> Dear Matlab community,
>
> I am currently facing a little issue:
>
> I have a matrix with share volume (SHVOL) and shares outstanding
> (SHROUT). Both are over the same time period and the same companies, of
> course. Since the dataset is very long, it contains a lot of NANs.
>
> I would like to compute share turnover (TURNO), which is
> (SHVOL)/(SHROUT). I use the following code for that:
>
> TURNO = (abs(SHVOL)./abs(SHROUT);
>
> after that, I want to compute the mean turnover (mTURNO) for each period:
>
> mTURNO = nanmean(ans(TURNO),2);
>
> nanmean computes the mean while ignoring NANs, and 2 indicates a mean of
> column values.
>
> Mast values of my (n x 1) mTURNO matrix look fine, but some of them
> state 'inf'. There is clearly some error. Does anyone have a suggestion
> how to fix it?
>
...

More than likely you've created some Inf values in the division step --
if SHROUT --> 0 and SHVOL isn't, that's going to be the result. What is
the proper thing to do is dependent upon the analysis--removing such
from the dataset might be a starting point unless the time is also
significant.

As an aside, why the abs(); aren't both volume and turnover just quantities?

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