See if this helps. No calc field, just summary fields, but shown in single-row portal (filtered or not)
-- sent from my iPhone4 --
Thank you for your reply.
I traded out the calc fields for summary fields. I had already set up each portal as a single-row portal. The change made no difference in the load time.
Unless I'm doing something wrong, I think I'm just asking too much for the computing power of the phone.
Portal filtering is inherently slower than filtering via relationship, and is really only useful for smaller related sets. Try to implement as much filtering via relationships as possible (e.g. use several global fields to match the year fields for the different portals), and offer additional portal filter functionality for the respective result sets.
If necessary, replace calculations and summaries with indexed fields that you write on creation or editing of pertinent related fields, and/or use a table to hold pre-summarized results (e.g. total figures per month/year per category etc.) that you also maintain via scripting.
I haven't created the table to hold subtotals yet, but by having the relationships do the heavy lifting for filtering, I was able to cut the load time for this particular layout on the iPhone from 15 seconds down to 5.