# Fastest way to calculate IRR (TIR)

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• 03-07-2008, 04:28 AM
unix
Fastest way to calculate IRR (TIR)
Iīm currently doing some financial calculations on my 50g, using
"Finanzas HP49g" by Erick Valverde Aguilera.
Great library indeed but IRR (Internal Rate of Return or Tasa Interna
de Retorno in spanish) calculations are quite slow sometimes.

I wonder if anybody is aware of whatīs the fastest way of doing this
kind of calculations on a 50g.

Itīd be amazing if someone knowledgeable on HPGCC would release an
ultra-fast financial solver.

Thanks.
• 03-07-2008, 06:35 AM
unix
Re: Fastest way to calculate IRR (TIR)
Iīm currently doing some financial calculations on my 50g, using
"Finanzas HP49g" by Erick Valverde Aguilera.
Great library indeed but IRR (Internal Rate of Return or Tasa Interna
de Retorno in spanish) calculations are quite slow sometimes.
I wonder if anybody is aware of whatīs the fastest way of doing this
kind of calculations on a 50g.
Itīd be amazing if someone knowledgeable on HPGCC would release an
ultra-fast financial solver.
Thanks.

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You might consider a Modified Dietz instead. And a practical use of a
Modified Dietz would simply be to set gain or loss against an average
balance so that a big deposit or a big withdrawal does not misrepresent the
fundamental gain or loss...

Here is a user link to KBH Investor Accounting as an example:

[url]http://www.kbhscape.com/kbh.htm[/url]

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• 03-07-2008, 06:47 AM
unix
Re: Fastest way to calculate IRR (TIR)

[color=blue]
>
> You might consider a Modified Dietz instead. And a practical use of a
> Modified Dietz would simply be to set gain or loss against an average
> balance so that a big deposit or a big withdrawal does not misrepresent
> the fundamental gain or loss...
>[/color]

That's set the gain or loss against an average deposit-withdrawal balance...

• 03-08-2008, 12:14 AM
unix
Re: Fastest way to calculate IRR (TIR)
On Thu, 06 Mar 2008 22:28:38 -0600, jdoliva wrote:
[color=blue]
> I'm currently doing some financial calculations on my 50g,
> using "Finanzas HP49g" by Erick Valverde Aguilera.
> Great library indeed but IRR (Internal Rate of Return or Tasa Interna
> de Retorno in spanish) calculations are quite slow sometimes.[/color]
[color=blue]
> I wonder if anybody is aware of what's the fastest way
> of doing this kind of calculations on a 50g.[/color]

Problems which can be expressed as a polynomial
(evenly spaced cash flows) can be solved directly
by the built-in PROOT command (discarding all complex roots);
a simple IRR (and TVM) program based on this was posted here:
[url]http://groups.google.com/group/comp.sys.hp48/msg/fba69b8f240340d4[/url]

The built-in numerical solver (ROOT) can be hugely faster, however,
when a reasonable formula and feasible initial guess are used,
particularly if the number of cash flows is large,
as illustrated in this case of 100 cash flows:
[url]http://groups.google.com/group/comp.sys.hp48/browse_thread/thread/17a7bb597a5f0116[/url]

An "irregular cash flows" solver (speed unknown) is part of this package:
[url]http://www.hpcalc.org/search.php?query=fin49[/url]
[color=blue]
> It'd be amazing if someone knowledgeable on HPGCC
> would release an ultra-fast financial solver.[/color]

How many large projects do you need to evaluate per second? :)

Good technique is often of more value than brute force.

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