plots of semilogx or semilogy gone wrong

Hey, I sometimes notice that MATLAB refuses to plot in a logarithmic x- or y-scale, even though there are no zero or negative values present in the plotdata. Instead, MATLAB chooses to plot in linear scales. Is there anyone who recognises this? Or can someone explain me which criterium MATLAB uses here, because it seems a bit arbitrary to me.

Thanks in advance, Bart

[Arnaud Miege]

Can you provide an example?

[John D'Errico]

Without an example where this happens, we can only assume that you have committed some strange mistake, since nobody else that I have ever heard of has said this happens to them. It has certainly never happened to me. So please give an example where this occurs. Even better, if you can find such a case where that happens consistently on a given set of points, send it in to TMW as a bug report.

[Walter Roberson]

plot can do some strange things if your data exceeds +/- 10^100; is that a possibility in your situation?