41C/CV root finders

[Ángel Martin]

(05-26-2015 05:39 PM)Dieter Wrote:  OK. But back to the initial guess: does it really evaluate to 165% for the sample case, or did I understand something wrong?

Not sure I follow, I didn't try the example before - but I just ran it an here are the results:

10 = (n)
50 = (PV)
–30 =(PMT)
400 = (FV)

I=14.43587035% in end mode, and
I=10.20509732% in begin mode

you can also run it yourself on V41 of course...

(05-26-2015 05:39 PM)Dieter Wrote:  How many iterations are required for the example posted in this thread until the result (14,436%) is returned? Does the algorithm actually return the lower one of the two solutions (the other one being 53,172%), although the first estimate is as high as 165%? Since |PV+n*PMT+FV| usually is > 1, the estimate will (almost) always be > 100%.

And finally... may I ask this...? Would you mind trying your algorithm with a first estimate of 1E–4? How does it behave?

I'd need to put breakpoints in the code to read the initial guess and the number of iterations, let me work on that and I'll get back to you tomorrow.

Cheers,
'AM