semilogy set scale

[Benjamin Sapp]

Hi,

I am saving a bunch of .png plots made with the semilogy function.  I'm 
then using the gimp to create a gif animation.   I'm really pleased with 
the results except one problem.  The problem is that the y axis changes in 
the plots and I'd like it to remain constant across all plots.  That way 
people can see the changes in the plot without thinking about the changes 
in the scale.   Do you know how to force a particular axis on the semilogy 
function?

Thanks,
Ben.