function calculation in cytoscape doesn't work

[Roberta]

Hi everyone.

I am visualizing networks on Cytoscape from .graphml files. Those files consist basically in lists of amino acids sequences each one with a certain frequency. Now, I would like to visualize the nodes of my network sized as logarithmic frequency-based, but when I try to calculate the log of the frequency from the f(x) command in Cytoscape, it turns into an error (#ERR: can't convert "frequency [,10]" to a number in a call to LOG()).

Do you know have any idea about what is happening? 

Please, ask me for further information if I haven't been clear enough.

Thanks!