HP Forum Archive 15

[ Return to Index | Top of Index ]

Don't buy the 17BII+ !! Message #1 Posted by Vincent Weber on 6 June 2005, 4:32 a.m. Hi all, I had a discussion with Bob Wang (thanks Bob for the interesting Black Scholes equation). It is now very clear to me that the 17BII+ is a real piece of junk (no exaggerating). Let alone the plasticky look and feel, and the noisy keys, the software had no QA whatsoever. The first version did not have L() and G(). The second version does have them, but obviously there were not tested: they will "work" only if you write a dumb equation to initialize the temporary variables. On top of that, the solver is not stable. Sometimes it returns a correct answer, sometimes, you get 'overflow' or 'bad guesses' for simple, straitghforward, one root equations. God knows what else we will discover. As for me, I have given up on HP, the company that once produced quality devices. I am using the good old 17BII, 19BII, and my beloved 200LX. The programming model of the solver on these three is quite unique, well suited to finance people. I only regret 1) the lack of user-defined functions or subroutines and 2) the lack of break in loops. These could be easily added in a simulator on a PDA... I may work on this someday. There is no good simulation for these devices, even the so called 'HP-grade' solver of Powerone Finance does not support L() and G()... HP - rest in peace. Disgusted Vincent

Re: Don't buy the 17BII+ !! Message #2 Posted by Namir on 6 June 2005, 11:27 a.m., in response to message #1 by Vincent Weber Vincent, I am interested in examples of the 17BII+'s solver messing up. I have a presentation for HP calculator solvers in September at the HHC2005 in Chicago. Thanks, Namir

Re: Don't buy the 17BII+ !! Message #3 Posted by Vincent Weber on 6 June 2005, 5:54 p.m., in response to message #2 by Namir Hi Namir, Just consider the simple equation below: L(A:2*B)+G(A)=C First, if you don't initialize A with a dumb equation such as A+B=0, the G() function will return 0. That's a shame on its own, but that has already been covered in this forum. Now, after initialization, solving for C will work fine, i.e. return 4*<value of B>. But try to solve for A, regardless of the value of C, and it's another story. Depending on your wonderful 17BII+ mood, you will get 1)Overflow 2)Bad guesses or 3)(rarely) the correct answer. This seems to depend on the temperature and/or the speed of the wind... while I checked on 17BII AND 19BII AND 200LX, all 3 working -perfectly- fine. But these were other days. Cheers, Vincent

[ Return to Index | Top of Index ]

Go back to the main exhibit hall