33S SOLVE: What should have been done Message #9 Posted by Karl Schneider on 5 Sept 2004, 3:08 p.m., in response to message #7 by Gene
Gene posted,
Quote:
Hi Karl. Sorry you are frustrated, but this is not exactly a flash of news.
Hmmm. In view of your follow-up post titled, "And please don't take offense at the shortness of the title!", I guess I won't take you to task for that statement.
I'm certainly not frustrated per se about these somewhat-troubling things we are finding about the HP-33S -- after all, I have a wide assortment of "purebred" HP-designed-and-engineered calc's that do not have these issues.
Rather, I am disappointed that the designers of the 33S didn't "think things through" like HP did in the old days.
Thank you for giving me the "Learning Module" links. It spared me the trouble of plowing through HP's graphics-intensive, marketing-driven corporate website in search of information I wasn't sure would exist. Wlodek did indeed prepare useful explanations of the methods.
My points are two-fold:
1. This usage of direct-solutions by SOLVE in Equation mode should have been mentioned in the User's Manual. Users shouldn't have to navigate corporate websites without broadband and download graphical documents to find out why their calculator isn't performing intuitively, or as described in the printed manual they received in the package. I realize that the "direct method" techniques are new, and would not have been documented in the 32SII UM, but the 33S UM should have been enhanced.
2. The direct-solution procedures sometimes contradict the UM documentation, as illustrated in my example. I still believe that the direct method was not absolutely necessary, and the efforts to implement it might have been better spent in other areas too numerous to mention. However, there is some value in the procedure, and now that it has been done, here's a suggestion for HP to improve the logic:
STEP 1: Attempt to find the direct solution, if the format of the equation permits. Otherwise, try numerical iteration.
STEP 2: If a direct solution is found within the guess-range provided by the user, return the value and stop.
STEP 3: If a direct solution is found outside the range given by the user, store the value, and try numerical iteration.
STEP 4: If no direct solution can be found, try numerical iteration.
STEP 5: If a numerically-iterated solution is found within the guess-range provided by the user, return the value and stop.
STEP 6: If no iterated solution is found within the guess-range provided by the user, AND an outside-the-range direct solution was found in STEP 3, return that value and stop.
STEP 7: If an iterated solution is found outside the range given by the user, return that value and stop.
-- KS
Edited: 5 Sept 2004, 3:11 p.m.
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