Looking for TVM contributions

[dm319]

(05-24-2024 03:04 PM)Albert Chan Wrote:  Plus42 algorithm to check Plus42 may not show numbers are accurate.
Unless, of course, Rmpfr setup with much higher precisions to compensate.

Yes, throwing all the digits at it! And requiring the solver to reach the current precision, so I think it's fairly trustworthy for i. Though there's a question for you further down...

(05-24-2024 03:04 PM)Albert Chan Wrote:  Apply time-symmetry to reduce cancellation errors

Thank you Albert. As usual, it will take me several months before I start to understand this. However, this makes more sense now, as I couldn't understand why the plus42 code didn't have p in the equation. But sounds like you are inverting time to work this out? Clever!

I'm trying to work out how accurate plus42 and my solver is for this problem:

do_n(I%YR = 25%, PV = -100000, PMT = 2083.333334, FV = 0, p = 0)

and this one:

do_n(I%YR = 25%, PV = -100000, PMT = 2040.816327, FV = 0, p = 1)

Just curious what you would calculate the accuracy of plus42 for this? I'm using a lot of digits in R, but this one is more discrepant that usual.