See my blog article http://pitcher.digitalfreehold.ca/code/natlog
"This program computes the value of e to 5,000 decimal places, and
was inspired by
the article "The Impossible Dream: Computing e to 116,000 places
with a Personal
Computer" by Stephen Wozniak, published in Byte Magazine Vol 6,
Issue 6 (June 1981,
pp392)."
Ben Bacarisse said:The location of you reply suggests a connection between the article and
the series directly above it but I can't see a direct connection. The
last thing this thread needs is more confusion between e and gamma!
Ben Bacarisse said:The location of you reply suggests a connection between the article and
the series directly above it but I can't see a direct connection. The
last thing this thread needs is more confusion between e and gamma!
char const * ec( unsigned const n /* 0 <= n <= 30 */ )
{ static char result[ 33 ];
strncpy( result, "2.718281828459045235360287471352", n + 2 );
result[ n + 2 ]= 0;
return result; }
If you're actually interested in particating here, then please
(a) format your text in lines shorter than 80 columns, preferably
around 72 and (b) quote some context from the article to which you're
replying (see 99% of the followups here for examples; Google Groups
can make this difficult, but the "old" interface isn't as bad as
the new one).
Le 21/11/11 16:08, 88888 Dihedral a écrit :
You can download it at no cost fromhttp://www.cs.virginia.edu/~lcc-win32
It's evolved almost quite far enough, and perhaps too far in some
directions. I think that's one of its beauties, it's still recognisable
as the language I first saw in the 80s.
I was reading about a <ahem> very closely related language recently and
was delighted to see that a feature that was standardized after I last
seriously used the full language, about 10 years ago, is now deprecated.
The "designers", and I use the term very loosely - they're clearly
bodgers who can't think things through thoroughly enough, of that
language should be taken outside and whipped. And their language derided
for the mess that it is.
Oh - do you not think that a 15-line long .sig is a bit excessive
attached to a post with only two lines of original text?
[email protected] (Stefan Ram) said:Ben Bacarisse said: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)
The location of you reply suggests a connection between the article and
the series directly above it but I can't see a direct connection. The
last thing this thread needs is more confusion between e and gamma!
char const * ec( unsigned const n /* 0 <= n <= 30 */ )
{ static char result[ 33 ];
strncpy( result, "2.718281828459045235360287471352", n + 2 );
result[ n + 2 ]= 0;
return result; }
Good one! You reply to a post about the potential for confusion between
the posted series and e by posting a function to compute e.
Since this seems to be a solution to the OP, could you not have replied
to that message?
(Also, I think it's good to mark where you cut text out. Better still
is to cut anything not needed for context. You cut all of Lew's text,
to which you code *does* relate, but you left mine and Jacob's to which it
does not.)
Nick Keighley said:in what way does google groups make proper quoting difficult?
Kleuskes & Moos said:Provided for your amusement only. The argument of conserving bandwidth
may have been valid 20 years ago, nowadays it's hardly valid.
They've introduced a new user interface that's much worse than the
older one, at least for purposes of posting to Usenet. I don't
remember the exact details. Last time I checked, you don't get the
new interface unless you request it, and you can still go back to
the old one.
Bandwidth isn't the only issue. It takes up space on everyone's screen
that could be used to show more useful information. (And frankly they
aren't all that amusing.)
At least use a proper signature delimiter (a line consisting of "-- ").
above loop end with exaustation of memory
without return one result
yes but i'm a little ot because it is C++...
yes but i'm a little ot because it is C++...
So, let's try something /on-topic/, then, shall we?
/*
** This program was inspired by the article "The Impossible Dream:
** Computing e to 116,000 places with a Personal Computer" by
** Stephen Wozniak, published in Byte Magazine Vol 6, Issue 6
** (June 1981, pp392).
**
** Essentially, the following program implements a partial expansion
** of the equation: e = 1 + (1/1!) + (1/2!) + (1/3!) + ... + (1/n!)
** by inverting the equation, such that it reads...
** e = (((((...(((((1/n) + 1) / (n-1)) + 1) ... / 3) + 1) / 2) + 1) /
1) + 1
**
** I originally wrote this program in Z80 Assembler code, to run under
** CP/M (Dec 1986), and subsequently have recoded the program in
** 370 Assembler to run under MVS and VSE, and C to run under MSDOS
** and Linux
**
** Lew Pitcher, 1999
*/
#include <stdio.h>
#define I 1 /* number of bytes in integer portion */
#define X 2078 /* number of bytes in fraction portion */
#define N 1776 /* number of divide iterations */
#define P 5000 /* number of multiply iterations */
char e[I+X]; /* holds fixed point binary value of e */
int main(void)
{
void divide(char *, unsigned, unsigned),
multiply(char *, unsigned, unsigned);
unsigned n, /* divisor for calculation loop */
p; /* precision for print loop */
e[0] = 1; /* start the series at 1.anything */
for (n = N; n > 0; --n)
{
divide(e,n,I+X);
e[0] += 1;
}
fputs(" e == ",stdout); fputc(e[0]+'0',stdout); fputc('.',stdout);
for (p = 0; p < P; ++p)
{
e[0] = 0;
multiply(e,10,I+X);
fputc(e[0]+'0',stdout);
if (p%5 == 4)
if (p%50 == 49)
fputs("\n\t",stdout);
else
fputc(' ',stdout);
}
fputc('\n',stdout);
return 0;
}
void divide(char *dvd, unsigned dvr, unsigned prc)
{
char *Wk_q;
unsigned bit, rmdr;
rmdr = 0;
for (Wk_q = dvd; Wk_q < dvd+prc; ++Wk_q)
{
for(bit = 0; bit < 8; ++bit)
{
rmdr *= 2;
if (*Wk_q & 0200) rmdr += 1;
*Wk_q <<= 1;
if (rmdr >= dvr)
{
*Wk_q += 1;
rmdr -= dvr;
}
}
}
}
A division of a long integer with a known length of bytes by an integer of 8 to
1bits in a digit by digit division which that every digit is at least 8 bits is
still missing.
This is trivial in C, but I'll see if we have to start a c programmingrace here.
I know that a division in C in some compiler in most CPUs is really slow. I write that in assembly.
Lew Pitcher ha scritto: [snip]for (p = 0; p < P; ++p)
{
e[0] = 0;
multiply(e,10,I+X);
fputc(e[0]+'0',stdout);
if (p%5 == 4)
if (p%50 == 49)
here my compiler says:
temp.c: In function ‘main’:
temp.c:50: warning: suggest explicit braces to avoid ambiguous ‘else’
I know that a division in C in some compiler in most CPUs is really slow.
I write that in assembly.
Do you? Would you tell me what you know about division that the compiler
writer doesn't know?
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