What's the hardest (longest-running) financial calculation?

[EdS2]

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Hi Valentin,
thanks for the links. As advised, I skimmed the heavy financial papers very lightly, and am quite relieved I don't need to study them. Your HP-12C Serendipitous Solver paper is very much to the point - thanks for that - I've read it at least a couple of times before but this is the first time for me where the runtimes are the important part.

So, to summarise from that paper, the timings for presumably an original-model 12C for various IRR computations are:
11 seconds for a 4 element cashflow (Fibonacci's cubic) (14 keypresses to enter?)
18 seconds for an 8 element cashflow with only 4 groups of terms (19 keypresses?)
3 min 20 sec for a 138 element cashflow with only 5 non-zero terms (29 keypresses?)

(Edit: Those keypress counts are in addition to a 37 step program which offers polynomial solving using the IRR feature. I imagine one could enter the cashflows directly. I put the question marks in because I might have miscounted and the number isn't critical anyway.)

That seems to me like a good range of times, suitable for benchmarking financial calculators with a range of performance!

I might start a new thread about the various offerings from HP of financial calculators.

Thanks again
Ed