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| From | Markus Wichmann <nullplan@gmx.net> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Euler's constant |
| Date | 2011-11-21 14:10 +0100 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <38vpp8-qf8.ln1@voyager.wichi.de.vu> (permalink) |
| References | <24357587.77.1321816326271.JavaMail.geo-discussion-forums@prnv30> <jaddl0$eb6$1@speranza.aioe.org> |
On 21.11.2011 12:45, jacob navia wrote:
> Le 20/11/11 20:12, 88888 Dihedral a écrit :
>> PROBLEM 1: COMPUTE THE EULER'S NUMBER UP TO 30 DIGITS AFTER 1.
>> THE DIGIT REQUIRED SHOULD BE PARAMETER BY THE CALLER!
>
> Euler's constant is the limit of the sum when N goes to infinity of:
>
> 1 + 1/2 + 1/3 + 1/4 + ... 1/N - ln(n)
>
Nope., but nearly. Perhaps you want to research the "harmonic series"
(or whatever name they gave it in english...). That series is divergent,
the reason being: For any natural number n there is a natural number m
so that Sum(i=0..m, 1/(n+i)) > 1. So the harmonic series adds up an
infinite number of ones and thus goes straight to Infinity. (Or rather,
any number you care to name gets exceeded by that series eventually.)
Euler's number is actually
1+ 1 + 1/2! + 1/3! + 1/4! + ...
So... to calculate the Euler number you'd actually need to keep track of
the current addend. Dunno, something like
e = 2;
factorial = 1;
fact_arg = 2;
for(;;) {
factorial *= fact_arg++;
addend = 1/factorial;
e += addend;
}
Filling in the blanks and propably finding a decent library to code the
stuff with (or writing the library yourself... it is not hard if all you
want to do is multiplying and adding and you can wait a bit) is left as
an excercise to the reader.
> This is related to the PSI function (digamma) by
>
> Euler constant = -psi(1)
>
> This can be calculated in C with this program:
> (Using lcc-win. Other compilers will be able to do this too
> but in a different way)
>
So... basically you say this cannot be done in ISO C? Or is it just to
hard? Or do you want to promote yourself? And what the hell is psi()
meant to be? My man page collection doesn't know it and it knows stuff
like bessel functions...
Basically, I think we can all agree on the fact that a normal float or
double won't yield enough precision for thirty decimal places. On a
machine using IEEE 754 floating point types, a double has fifty two
binary places. That's 52*lg(2)~~ 15.6 decimal places. So we'd actually
have to write a multiprecision integer (for the factorial stuff) and
floating point library.
> d:\lcc\mc79\test>type teuler.c
> #include <qfloat.h>
> #include <specialfns.h>
> #include <stdio.h>
> int main(void)
> {
> qfloat e=psiq(1.0q);
> printf("Euler constant is:\n%.95qf\n",-e);
> }
>
So, not only does this program feature strange types, it also has
unknown suffixes to literals and extensions to printf().
I don't know exactly, but I'd file this code under "Not C"!
HTH,
Markus
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OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-20 11:12 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Ian Collins <ian-news@hotmail.com> - 2011-11-21 08:18 +1300
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-11-20 20:22 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-20 11:23 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-20 15:03 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kaz Kylheku <kaz@kylheku.com> - 2011-11-20 20:06 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-20 12:13 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Ian Collins <ian-news@hotmail.com> - 2011-11-21 09:16 +1300
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-20 15:37 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-11-20 14:15 -0700
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-20 13:45 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-21 00:44 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-21 12:44 +0200
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-21 10:41 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 00:53 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! "io_x" <a@b.c.invalid> - 2011-11-24 19:08 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Martin Ambuhl <mambuhl@earthlink.net> - 2011-11-20 17:32 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-20 14:55 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-20 16:54 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-20 19:35 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-22 00:39 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-22 13:18 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-24 01:50 -0800
Re: Euler's constant jacob navia <jacob@spamsink.net> - 2011-11-21 12:45 +0100
Re: Euler's constant Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-11-21 13:54 +0100
Re: Euler's constant jacob navia <jacob@spamsink.net> - 2011-11-21 14:48 +0100
Re: Euler's constant Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-11-21 18:58 +0100
Re: Euler's constant Markus Wichmann <nullplan@gmx.net> - 2011-11-21 14:10 +0100
Re: Euler's constant jacob navia <jacob@spamsink.net> - 2011-11-21 15:36 +0100
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 07:08 -0800
Re: Euler's constant jacob navia <jacob@spamsink.net> - 2011-11-21 16:16 +0100
Re: Euler's constant Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-22 00:44 -0800
Re: Euler's constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-21 15:33 +0000
Re: Euler's constant Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-21 08:50 -0800
Re: Euler's constant "BartC" <bc@freeuk.com> - 2011-11-21 17:13 +0000
Re: Euler's constant James Kuyper <jameskuyper@verizon.net> - 2011-11-21 12:29 -0500
Re: Euler's constant Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-21 09:28 -0800
Re: Euler's constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-21 23:07 +0000
Re: Euler's constant Kaz Kylheku <kaz@kylheku.com> - 2011-11-21 17:29 +0000
Re: Euler's constant James Kuyper <jameskuyper@verizon.net> - 2011-11-21 12:36 -0500
Re: Euler's constant Keith Thompson <kst-u@mib.org> - 2011-11-21 13:46 -0800
Re: Euler's constant "io_x" <a@b.c.invalid> - 2011-11-24 19:08 +0100
Re: Euler's constant Markus Wichmann <nullplan@gmx.net> - 2011-11-24 20:31 +0100
Re: Euler's constant "io_x" <a@b.c.invalid> - 2011-11-27 11:24 +0100
Re: Euler's constant Markus Wichmann <nullplan@gmx.net> - 2011-11-27 12:09 +0100
Re: Euler's constant "io_x" <a@b.c.invalid> - 2011-11-27 13:33 +0100
Re: Euler's constant Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-21 10:44 -0800
Re: Euler's constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-21 22:53 +0000
Re: Euler's constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-21 23:51 +0000
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-22 04:17 -0800
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-27 17:50 -0800
Re: Euler's constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-28 03:09 +0000
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-28 02:52 -0800
Re: Euler's constant Seebs <usenet-nospam@seebs.net> - 2011-12-28 18:17 +0000
Re: Euler's constant Dr Nick <3-nospam@temporary-address.org.uk> - 2011-12-28 18:49 +0000
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-04 04:44 -0800
Re: Euler's constant Robert Wessel <robertwessel2@yahoo.com> - 2012-01-04 12:33 -0600
Re: Euler's constant 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 15:07 -0800
Re: Euler's constant "io_x" <a@b.c.invalid> - 2011-11-24 19:08 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 04:00 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-11-21 12:37 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 04:45 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-11-21 13:35 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-22 00:01 +0200
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-11-22 11:53 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-22 13:21 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kleuske <kleuske@nowhere.net> - 2011-11-24 14:50 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! "io_x" <a@b.c.invalid> - 2011-11-24 14:08 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! "io_x" <a@b.c.invalid> - 2011-11-24 18:02 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-25 15:31 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-25 17:40 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-25 22:03 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-25 22:43 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Joe Wright <joewwright@comcast.net> - 2011-11-26 02:13 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-26 19:40 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-27 15:35 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Ian Collins <ian-news@hotmail.com> - 2011-11-26 20:22 +1300
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-26 10:55 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Seebs <usenet-nospam@seebs.net> - 2011-11-28 08:32 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! superpollo <superpollo@tznvy.pbz> - 2011-11-26 12:11 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-26 10:37 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! superpollo <superpollo@tznvy.pbz> - 2011-11-26 21:48 +0100
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-28 01:56 -0800
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-28 13:34 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! James Kuyper <jameskuyper@verizon.net> - 2011-11-28 13:45 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Lew Pitcher <lpitcher@teksavvy.com> - 2011-11-28 13:50 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! James Kuyper <jameskuyper@verizon.net> - 2011-11-28 14:32 -0500
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Kleuske <kleuske@nowhere.net> - 2011-11-28 21:16 +0000
Re: OK. LETS START REAL PROGRAMMING IN C FOR PROBLEMS!!! Keith Thompson <kst-u@mib.org> - 2011-11-28 14:59 -0800
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