Most mindblowing program for your favorite calculator

06182022, 01:53 AM
(This post was last modified: 06182022 06:10 AM by pauln.)
Post: #1




Most mindblowing program for your favorite calculator
I'm more specifically thinking in terms of memory constraints (steps/registers): a program that, at first sight, could not possibly fit in the given calculator.
My choice for the TI59 would be "1287 digits of pi". In order to achieve this, one needs to use all the digits (including the hidden ones) of 99 of the 100 available registers using 160 steps or less. I have never tried to run the program but I'm guessing the last 5 digits or so are incorrect because of accumulating rounding errors. What about for your favorite calculator? 

06182022, 03:29 AM
(This post was last modified: 06182022 03:38 AM by Steve Simpkin.)
Post: #2




RE: Most mindblowing program for your favorite calculator
I don’t know if this qualifies but in retrospect it seems kind of far fetched by today’s standards.
I bought my HP25 in 1977 and used it though high school, four years of college, and my first two years of work as an engineer. While I wrote many small programs to automate tasks, the most complex one was for a project at work around 1984. I had to create a table of elevations and compass headings used to aim a portable 5 foot satellite dish at the Galaxy II geostationary television satellite from about 200 latitude/longitude locations across north America. I obtained the required formulas from a library book, wrote the program, entered it into my HP25, plugged it into AC power and away I went. At the time I didn't have access to a computer with a printer. The "company" computer filled a LARGE room, used punch cards and no one, including the people who manned it, knew how to write new programs for it. The latitude/longitude locations were provided for selected cities in the U.S. that I would have had to enter manually anyway. The HP25 did the job in a fraction of the time and effort any other method would have required. You really could do a lot with 49 steps of program memory. HP product do "fill real needs, and provide lasting value". 

06182022, 04:18 AM
Post: #3




RE: Most mindblowing program for your favorite calculator
(06182022 03:29 AM)Steve Simpkin Wrote: You really could do a lot with 49 steps of program memory. Certainly: 49 fullymerged program steps, RPN and the ability to go to an arbitrary step without declaring a label. I'm not sure how programmers were dealing without subroutines though. Does anybody know why 49 steps and not 50? Seems like a really odd number to me. 

06182022, 04:49 AM
(This post was last modified: 06182022 04:51 AM by Steve Simpkin.)
Post: #4




RE: Most mindblowing program for your favorite calculator
(06182022 04:18 AM)pauln Wrote:(06182022 03:29 AM)Steve Simpkin Wrote: You really could do a lot with 49 steps of program memory. The HP25 had an external data chip with sixteen 56bit registers. Each 56bit register could hold one BCD number or 7 steps (bytes) of program memory. One register was used for LAST x, 8 for memory registers and 7 for program memory. Thes last 7 registers with 7 bytes each made a total of 49 program steps. See the Nov 1975 issue of HP Journal for more information. https://www.hpl.hp.com/hpjournal/pdfs/Is...97511.pdf 

06182022, 05:44 AM
Post: #5




RE: Most mindblowing program for your favorite calculator
Thanks, that makes a lot of sense.
For reference, the TI57 had a little bit more memory with sixteen 64bit registers, which explains the 11digit mantissas in the TI57 as opposed to the 10digit mantissas in the HP25. 

06182022, 06:38 AM
Post: #6




RE: Most mindblowing program for your favorite calculator
Weakest calculator/pocket computer that can do Tower of Hanoi?
(08112018 06:52 PM)Dave Britten Wrote: Now that would be impressive to see it running on a 25. Solution (HP65) NQueens (01132022 10:49 PM)Dave Britten Wrote: I've been thinking over whether I can cram this onto the HP 25, but it's not coming to me so far. If anybody can manage that, I'll be really impressed... (25) NQueens (29C) Prime numbers up to 10'000 (09042018 12:04 AM)Archilog Wrote: A guy called C.Ret did an awesome work which can be found there: Silicium ... In French. But the most interesting is easily readable. How about a pocket / hand held RPL calc? Quote:Still, if you want to really impress me and, at the same time, make me a true believer of the 17's programming capability, write a version of the Nqueens benchmark program for the 17bII+, execute it, and submit the time. ;^) As of yet, nobody has done this. Personally, I think this is a golden opportunity to prove all the naysayers wrong  if possible. Equation for the 8queens problem And then we have this pearl: Gaussian integration for the HP11C 

06182022, 04:35 PM
Post: #7




RE: Most mindblowing program for your favorite calculator
Thanks for the list. To me, the NQueens for the HP25 is especially mindblowing in the sense that, if I had to bet, I would have said "no way, that's not possible".


06192022, 06:06 PM
Post: #8




RE: Most mindblowing program for your favorite calculator
The HP25 solution of Nqueens is one of my favorites. Very impressive.
The most challenging program on my very first programmable calculator, the FX180P, was the Collatz conjecture. First I thought, that it's not possible to write a program for the output of the number of interations and the maximum. But after some effort I managed to do it. Code: 01 2 Calculator Benchmark 

06192022, 06:34 PM
Post: #9




RE: Most mindblowing program for your favorite calculator
I had a TI59 program in about 1983 with around 1500 steps. Since the '59 didn't have that much memory, I had it prompt for different cards when needed, kind of like discswapping. I don't remember anymore what the program was for.
http://WilsonMinesCo.com (Lots of HP41 links at the bottom of the links page, http://wilsonminesco.com/links.html ) 

06302022, 07:34 AM
Post: #10




RE: Most mindblowing program for your favorite calculator
The "smallest but workable" is more hard task and required more effort to produce, I guess. Here are three from my head during last decade:
1.) Factorial (3 steps) for HP12C for 1, 2, ..., 69 integers: Factorial (3 steps) HP12C 2.) GCD (8 steps) for HP15C without MOD: GCD (Greatest Common Divisor) for HP15C (8 steps) without MOD 3.) Linear regression coefficients (7 steps) for HP12C: Linear regression coefficients (7 steps) for HP12C +1 Bonus) Secant methon on CASIO fx50F (14 steps) Code:
nJoy! Cs. 

06302022, 03:40 PM
(This post was last modified: 06302022 03:41 PM by Maximilian Hohmann.)
Post: #11




RE: Most mindblowing program for your favorite calculator
Hello!
(06192022 06:34 PM)Garth Wilson Wrote: I had a TI59 program in about 1983 with around 1500 steps. Since the '59 didn't have that much memory, I had it prompt for different cards when needed, kind of like discswapping. I don't remember anymore what the program was for. I still have four cards for my Ti59 that were required to numerically solve a system of differential equations. This must have been around the same year, 1982 or 83, part of an excercise for a university course "numerical methods for solving differential equations in engineering" (or similar). The alternative to swapping cards on my Ti59 at home would have been to queue in front of a keypunch at the university computer center. That was probably the most intense thing I ever did with a programmable calculator, although I would not call it "mind blowing" as in the thread title. Rather brute force or "not using the right tool for the job". Regards Max 

06302022, 04:36 PM
Post: #12




RE: Most mindblowing program for your favorite calculator
(06302022 03:40 PM)Maximilian Hohmann Wrote: although I would not call it "mind blowing" as in the thread title. Rather brute force or "not using the right tool for the job". LOL. Well, I got the TI58c in Dec '81 for $100 at Jewelcor (remember those stores, which sold jewelry, electronics, cameras, etc.?), and perhaps a year later was in the right place at the right time to trade it and another $100 for a 59 and printer and some extra modules. I have a friend who paid $3K for an Apple II and extra memory and accessories probably a little before that, and the Commodore 64 would come out just after that for $600 (and monitor, disc drives, etc. were extra). There were no laptops yet, and the home computers were not portable like a calculator that took only a corner in the attache case. I took a class in FORTRAN IV in '82 at the local community college, and of all our assignments, I could get results much faster with my calculator than I could writing out the FORTRAN on coding sheets, going to the computer lab at school and sitting at the cardpunch machine, then rubberbanding the set, along with my account number, and putting it in a cubby and coming back a couple of hours later hoping they had run it, only to find a printout of all the reasons it wouldn't run, and have to repeat this noninteractive process. It was kind of like in the movie "The Computer Wore Tennis Shoes" (the original from 1969, not the later 1995 one), where Medfield College was given this computer, free, because it was already so outdated. http://WilsonMinesCo.com (Lots of HP41 links at the bottom of the links page, http://wilsonminesco.com/links.html ) 

06302022, 05:22 PM
(This post was last modified: 06302022 05:51 PM by Dan C.)
Post: #13




RE: Most mindblowing program for your favorite calculator
(06192022 06:06 PM)xerxes Wrote: The most challenging program on my very first programmable calculator, the FX180P, was the Collatz conjecture. First I thought, that it's not possible to write a program I must try this, the FX180P was my first real technical calculator! I used it in the "Gymnasiet" in Sweden, and FX180P was a very popular machine in Sweden at that time. I have the FX180P still, and its in a good working condition. edit: Isnt the FX180P the same machine as the FX3600P, but in a different housing? 

06302022, 07:59 PM
Post: #14




RE: Most mindblowing program for your favorite calculator
(06192022 06:34 PM)Garth Wilson Wrote: I had a TI59 program in about 1983 with around 1500 steps. Since the '59 didn't have that much memory, I had it prompt for different cards when needed, kind of like discswapping. I don't remember anymore what the program was for. Could that have been the program to calculate speaker crossover networks? 

06302022, 08:57 PM
Post: #15




RE: Most mindblowing program for your favorite calculator
(06302022 07:59 PM)KeithB Wrote: Could that have been the program to calculate speaker crossover networks? No, but it seems to be missing from my files, so I can't find what it might have been. It might have had to do with my amateurradio hobby. http://WilsonMinesCo.com (Lots of HP41 links at the bottom of the links page, http://wilsonminesco.com/links.html ) 

07012022, 03:00 AM
Post: #16




RE: Most mindblowing program for your favorite calculator
(06302022 04:36 PM)Garth Wilson Wrote:(06302022 03:40 PM)Maximilian Hohmann Wrote: although I would not call it "mind blowing" as in the thread title. Rather brute force or "not using the right tool for the job". Ha! I took a Fortran class at Cal Poly Pomona, California in 1983 and it was the same exact process! Sometimes my batch did not get run until the following day. It took forever to debug a program this way. It really encouraged you write it carefully the first time so you wouldn't have to go through those time consuming steps. I had bought an Ohio Scientific Challenger 1P computer in 1979 ($350) and had written a number of BASIC programs before this class. Using punch cards and waiting for your program to be run seemed like a huge step backwards compared to my rather primitive Challenger (which I still have). I understand they got rid of the cardpunch machines at that college the following year. I also remember Jewelcor. I bought my HP11C at one in 1987 ($56). I think they went out of business a few years after that. 

07012022, 05:02 AM
Post: #17




RE: Most mindblowing program for your favorite calculator
(06302022 07:34 AM)Csaba Tizedes Wrote: 2.) GCD (8 steps) for HP15C without MOD: GCD (Greatest Common Divisor) for HP15C (8 steps) without MOD These programs to calculate the GCD use only 5 steps: HP11C Code: 001  42 20 x>y HP15C Code: 001  43,30, 7 TEST 7 Example CLEAR PRGM 112 ENTER 63 R/S 7.0000 Remark: These steps must be the only ones in memory. Otherwise the program will not jump to the first line if the condition in line 005 is false. 

07012022, 05:38 AM
Post: #18




RE: Most mindblowing program for your favorite calculator
The nonmod version of Euclid's algorithm is prohibitively slow but you cannot argue against the elegance of this 5step solution.


07012022, 06:23 AM
(This post was last modified: 07012022 06:31 AM by Csaba Tizedes.)
Post: #19




RE: Most mindblowing program for your favorite calculator
(07012022 05:02 AM)Thomas Klemm Wrote: And what is the whole program if I want to use the calculator for other valuable tasks also, not only for stupid number theory?!? If you remove "LBL/RTN" and "GTO to first line" from my code, you got totally same... So it is not a really improvement, just lookslike improvement. Like give a blanket a homeless, instead of improving social circumstances. Thanks! Cs. 

07012022, 06:35 AM
Post: #20




RE: Most mindblowing program for your favorite calculator
(07012022 05:38 AM)pauln Wrote: The nonmod version of Euclid's algorithm is prohibitively slow Well, it depends. The worst case for the mod version is using two consecutive Fibonacci numbers. E.g. 144 and 89. \( \begin{matrix} a & b & n = \lfloor a \div b \rfloor & r = a  n \times b \\ 144 & 89 & 1 & 55 \\ 89 & 55 & 1 & 34 \\ 55 & 34 & 1 & 21 \\ 34 & 21 & 1 & 13 \\ 21 & 13 & 1 & 8 \\ 13 & 8 & 1 & 5 \\ 8 & 5 & 1 & 3 \\ 5 & 3 & 1 & 2 \\ 3 & 2 & 1 & 1 \\ 2 & 1 & 2 & 0 \\ \end{matrix} \) The nonmod version uses the same amount of steps but avoids division and multiplication. Thus it is even faster. However with something like 9,999,999,999 and 2 I totally agree. But in such cases you may calculate the remainder once manually to bring both numbers into the same ballpark. Of course you could still end up with a pathological case like 9,999,999,999 and 99,998 where that has to be repeated. But that is usually not the case. 

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