41C/CV root finders

[Ángel Martin]

(05-26-2015 10:08 PM)Dieter Wrote:  

(05-26-2015 09:26 PM)Ángel Martin Wrote:  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

That's close to the exact results (14,43587133% and 10,20509807%). I still wonder why an estimate > 100% leads to these results instead of the second, larger solutions.

Well, the initial guess is i0 = 0,01650475658, alas not greater than 100% (I don't remember saying anything about it being over 100% before, was than in another thread??), and the number of loops (iterations) needed is 7 for the "begin" case and 13 for the "end" case. On the CL (or V41 in turbo mode) it's obtained in the blink of an eye.

I'm positive my implementation isn't earth-shattering or novel-prize material Dieter, I just wanted to have a reliable TVM$ added to the SandMath on the 41 platform - using MCODE. So I wrote it from the scratch, not copied from the 12C or anything. Besides the i% solver it also has a very nice U/I that mimics the 12C design almost to the last detail, with alphanumeric characters for the results.

I guess what I'm saying is that it works for me and hopefully also does for other folks. Naturally will be nice to improve it, say implement the counter idea: how many loops are too many and where would you put the cut-off point?

Cheers,
'AM