Internal Rate of Return in Advanced Portfolio

[Wm...]

Fri, 13 Nov 2015 00:36:59 <DJmrItHrCTRWFwbn at tarrcity.demon.co.uk>
Wm... <tcnw81 at tarrcity.demon.co.uk> wrote...

[ff to self]

>One idea I've had, possible for the weekend, is to compile gnc 2.2.7 
>which I think the IRR scm was built for just to see what it does. [1]

>[1] at the moment I'm uncertain what the code in the IRR calc does.  Is 
>the Scheme code sufficiently clear to you to say what sums it is doing?

I installed 2.2.7 on a spare Win XP system and a test suggests the IRR 
figures are reasonable.

I used the flow in
===
https://support.office.com/en-us/article/IRR-function-64925eaa-9988-495b-
b290-3ad0c163c1bc
===
rather than real data as my example and get

an IRR of   8.66% vs their   8.7% after 5 years
an IRR of  -2.12% vs their  -2.1% after 4 years
an IRR of -44.30% vs their -44.4% after 2 years (no user guesses)

which is close enough not to matter.

So, if ThomasA or anyone else has a real-ish (i.e. sensibly munged) set 
of flows and an expected IRR that they'd like me to test (provide them 
in a convenient format, please) I'll plug them in and see what comes 
out.

Generally I'm now thinking this might be a worthwhile addition.

A thought: presuming the IRR is a good number should it be added to the 
extant Advanced Portfolio report or should we make a new report?  I'm 
wondering if the Advanced Portfolio report isn't getting overloaded, 
people are moaning about corner cases already, I think.

Observation: GnuCash 2.2.7 is noticeably faster than 2.6.9 and read my 
existing files without a moan.  Fun stuff!

-- 
Wm...