PI Decimals calculation on HP41c  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: PI Decimals calculation on HP41c (/thread72865.html) 
PI Decimals calculation on HP41c  Philippe  05032005 Hi everybody,
When I was a youg student, I used a program which allowed me to calculate thousands decimals digits of PI.
Philippe
Re: PI Decimals calculation on HP41c  Mike H  05032005 Try here: http://www.voidware.com/calcs/pi.txt
Re: PI Decimals calculation on HP41c  Philippe  05032005 THANK YOU MIKE!!!!!!
PHILIPPE
Re: PI Decimals calculation on HP41c  GWB  05032005 The best PI program for the 41C I know is one published in PPC Calculator Journal V7 N5 Page 9 June 1980, 'PI TO 1,110 PLACES' by Ron Knapp. pi=16 arctan (1/5)  4 arctan(1/239) Not the best method to calculate pi today, though. Anyway, it took "only" 11 1/2 hours to compute pi to 1000 places back then. Not bad considering that a contemporaneous Apple II program did that task in 40 hours. I've just run it on Emu42 running on my slow Pentium III: 1000 places in little less than 7 minutes. Regards, Gerson.
Deep Pi  Some Results  mark taylor  05042005 I've been running the Deep Pi program found on voidware.com on 3 different HP41CX's, each using an AC adapter, for several month now (continuously). Originally, the Deep Pi program calculated 6 digits of Pi at a time. But it was discovered that in at least one instance the 6th digit in a group was off by 1. Also, I modified the Deep Pi program by inserting a RUNSW and STOPSW to time the generation of each set of 6 digits. Those 2 commands appear at steps 2 and 9, respectively. Some results:
The first 6 digits of PI (after the 3) take about 38 minutes. The "deeper" into Pi you go the longer it takes. I'd never make it without the AC adapters plugged into the battery packs. I just love seeing my calculators really work. The Deep Pi program keeps my 41s cranking! Thanks Hugh Steers, for sharing Deep Pi on voidware.com.
Mark Taylor
Re: PI Decimals calculation on HP41c  Marc  05042005 Hi Philippe, Many years ago I played with the program published in "Science et Vie", and ported it to various calculators. By now the program is in my HP41 emulator, just for fun of course... Here it is :
01 LBL "PI"
Have fun !
Marc
Listing format problem !  Marc  05042005 Hi again ! I read my posting and saw that the carriage returns were mysteriously deleted, resulting in an unusable listing. Here's another one, without line numbers :
LBL "PI"
Marc
Re: Listing format problem !  Philippe  05042005 dear all,
Thank you all for your answers!!!! Philippe
SORRY MARC!!!  Philippe  05042005 Marc,
Disregard my previous mail.
Re: PI Decimals calculation on HP41c (with formatting)  Jeff O.  05042005 Marc, Hi Philippe,
Many years ago I played with the program published in "Science et Vie", and ported it to various calculators. By now the program is in my HP41 emulator, just for fun of course... Here it is : 01 LBL "PI"I remember it was a VERY slow program, even at that time. The constants at lines 10, 41 and 91 determine the number of decimals to be computed (100 => 1,000 decimals). Have fun !
Marc
Re: Listing format problem ! (with formatting)  Jeff O.  05042005 Marc, Hi again !
I read my posting and saw that the carriage returns were mysteriously deleted, resulting in an unusable listing. Here's another one, without line numbers : LBL "PI"I hope it'll be more readable. My apologies !
Marc
Jeff, thank you very much ! (NT)  Marc  05042005 ;)
Re: Deep Pi  Some Results  hugh steers  05062005 you’re most welcome, however, originally, i’d hoped the program would be interesting and find at least 1000 digits before slowing up too much, but in fact it slows up far too much way before that (eg around 200 digits).
the idea of calculating stateless digit portions of pi comes from here: http://numbers.computation.free.fr/Constants/Algorithms/nthdigit.html and this paper here:
http://numbers.computation.free.fr/Constants/Algorithms/nthdecimaldigit.pdf i did some work to improve and adapt this approach to calculators (10 digit overflow, for example). but its still not efficient enough. i'm hoping one, day the decimal version will be improved theoretically to make this an exciting possibility.
