Opening multiple files with

[Jason Snyder]

I am trying to open two files in GRADS with different time indices.  How can
I go about doing this.  I want to subtract the values in one file from the
values in the other file.  I have tried opening the files with XDFOPEN but
it does not work.  I am using GRADS 1.7.  Is there a more advanced GRADS
that can allow me to do this?

-Jason Snyder
University of California Davis