HP-41 Challenge: Double Integrals by INTEG Recursion

[Ángel Martin]

(05-30-2016 04:33 PM)hth Wrote:  I have not calculated an integral for 35 years, and never even heard of the existence of a double.

I know what you mean, but it gets even stranger: rumor has it there are even triples!!

(05-30-2016 04:33 PM)hth Wrote:  Sounds like an interesting programming challenge, I assume you want to swap in and out the buffer of the Advantage module, maintaining more than instance of the buffer. I look forward to your article, maybe I will (as you say) find time to take a stab at it, at some point in the future.

You're of course on the right track. The trick consists of changing the buffer-14 id# that is created by the first call to INTEG, so that when the second call happens it can create another buffer-14# and do its job on the second variable (X). Changing buffer id's is what function REIDBF does for a living, so there's a match made in heaven.

Timing and sync up are the only details to pay attention to. For instance there cannot be any key assignments (buffer-14# is placed BELOW those!) - The solution is simply to save them in XMEM at the beginning , clear them all, and restore them upon completion.

Cheers,
'AM