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Science Forum Index » Cryptography Forum » Long division algorithm
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| mike3 |
 Posted: Wed Dec 24, 2003 8:31 pm |
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Hi.
Could you please post a description of how to do long division of very
large numbers on a computer? I need one for the crypto program I'm
making. |
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| Tom St Denis |
| Posted: Wed Dec 24, 2003 8:46 pm |
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"mike3" <mike4ty4@yahoo.com> wrote in message
news:1d54b7e4.0312241731.1b6bc46b@posting.google.com...
Quote: Hi.
Could you please post a description of how to do long division of very
large numbers on a computer? I need one for the crypto program I'm
making.
http://math.libtomcrypt.org
v0.28 includes my textbook I'm working on [which happens to discuss
division].
So not only do you get the source code, a 89$ value but you get the 50$
textbook for the low low price of FREE!!!
;-)
Tom |
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| Douglas A. Gwyn |
| Posted: Thu Dec 25, 2003 12:40 am |
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"mike3" <mike4ty4@yahoo.com> wrote in message
news:1d54b7e4.0312241731.1b6bc46b@posting.google.com...
Quote: Could you please post a description of how to do long division of very
large numbers on a computer? I need one for the crypto program I'm
making.
Look up "multiple precision arithmetic" in any decent text on algorithms,
for example Kunth's "The Art of Computer Programming". |
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| Mok-Kong Shen |
| Posted: Thu Dec 25, 2003 7:44 am |
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mike3 wrote:
Quote:
Could you please post a description of how to do long division of very
large numbers on a computer?
A package for multi-precision arithmetic is in the book
H. Riesel, Prime numbers and computer methods for
factorization. The source is in Pascal but should be
readable for programmers of other PLs.
M. K. Shen |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 8:14 am |
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"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote in message
news:3FEADB96.DB8F53A2@t-online.de...
Quote:
mike3 wrote:
Could you please post a description of how to do long division of very
large numbers on a computer?
A package for multi-precision arithmetic is in the book
H. Riesel, Prime numbers and computer methods for
factorization. The source is in Pascal but should be
readable for programmers of other PLs.
I don't see how this is a good suggestion at all.
For starters, HAC is freely available on the web. So are the sources to
GMP, LibTomMath and half a dozen other libraries that sport division
algorithms.
Even if you don't like my free textbook [included in LTM v0.28, division is
on page 205 section 9.1] at least suggest reasonable alternatives. You
might as well be as insightful as Gwyn and suggest the poster go out and buy
Knuth just to learn division. [Though having Knuth around is a good idea
buying the book just to learn MP math is not].
Tom |
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| Mok-Kong Shen |
| Posted: Thu Dec 25, 2003 8:43 am |
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Tom St Denis wrote:
Quote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
......
[snip]
Quote: I don't see how this is a good suggestion at all.
For starters, HAC is freely available on the web. So are the sources to
GMP, LibTomMath and half a dozen other libraries that sport division
algorithms.
My possibly quite biased opinion is that the complete
Pascal package in Riesel is easier to read than other
sources.
Quote:
Even if you don't like my free textbook [included in LTM v0.28, division is
on page 205 section 9.1] at least suggest reasonable alternatives. You
might as well be as insightful as Gwyn and suggest the poster go out and buy
Knuth just to learn division. [Though having Knuth around is a good idea
buying the book just to learn MP math is not].
In most cases one could access textbooks in a public
library, that isn't a problem. (In many countries,
facilities of large libraries are accessible from
smaller ones.)
M. K. Shen |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 8:54 am |
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"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote in message
news:3FEAE99E.1178AF36@t-online.de...
Quote:
Tom St Denis wrote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
.....
[snip]
I don't see how this is a good suggestion at all.
For starters, HAC is freely available on the web. So are the sources to
GMP, LibTomMath and half a dozen other libraries that sport division
algorithms.
My possibly quite biased opinion is that the complete
Pascal package in Riesel is easier to read than other
sources.
That's a matter of opinion I guess. I'd say my LTM code is very easy to
follow. Specially considering I have a 300 page textbook that accompanies
it!!!
Quote:
Even if you don't like my free textbook [included in LTM v0.28, division
is
on page 205 section 9.1] at least suggest reasonable alternatives. You
might as well be as insightful as Gwyn and suggest the poster go out and
buy
Knuth just to learn division. [Though having Knuth around is a good
idea
buying the book just to learn MP math is not].
In most cases one could access textbooks in a public
library, that isn't a problem. (In many countries,
facilities of large libraries are accessible from
smaller ones.)
I have yet to see a library in Ottawa [the capital of Canada I might add]
which is public access and has crypto journals, CS textbooks or anything of
higher academic value.
Sure maybe if you want books on seals, indoor plumbing, self-help, crap for
dummies or the finer points of 1964 transistors [yes I found a book that old
in my college library on the subject] than you're set.
Tom |
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| Mok-Kong Shen |
| Posted: Thu Dec 25, 2003 9:01 am |
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Tom St Denis wrote:
Quote:
[snip]
I have yet to see a library in Ottawa [the capital of Canada I might add]
which is public access and has crypto journals, CS textbooks or anything of
higher academic value.
I suggest that you complain to, say, some members of
parliament that the Canadian public library system
is far from ideal. Note that networking of public
libraries is a nice idea.
M. K. Shen |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 9:09 am |
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"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote in message
news:3FEAEDA4.3351FDED@t-online.de...
Quote:
Tom St Denis wrote:
[snip]
I have yet to see a library in Ottawa [the capital of Canada I might
add]
which is public access and has crypto journals, CS textbooks or anything
of
higher academic value.
I suggest that you complain to, say, some members of
parliament that the Canadian public library system
is far from ideal. Note that networking of public
libraries is a nice idea.
I could but the problem is I have stuff todo. And truth be told the texts
do represent the people. Most people in Ottawa are not really into CS or
Math in any non "I want to make the $$$" sense so they're not likely to go
out and read a chapter or two of Knuth even if it were available [long rant
would follow here but it's christmas and I'm trying to keep it clean].
This is part of the reason why my stuff is free but I won't be as bold to
say my textbook is either finished enough for anything but the adventurous
students or sufficient enough to cover the theory behind the routines in
full detail. [I'll get there one day though]
Tom |
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| Mok-Kong Shen |
| Posted: Thu Dec 25, 2003 9:52 am |
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Tom St Denis wrote:
Quote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
I suggest that you complain to, say, some members of
parliament that the Canadian public library system
is far from ideal. Note that networking of public
libraries is a nice idea.
I could but the problem is I have stuff todo. ......
Spend some quarter of an hour and lots of your countrymen
(and even you yourself) might get benefits from that.
M. K. Shen |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 9:59 am |
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"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote in message
news:3FEAF9B8.D89470C5@t-online.de...
Quote:
Tom St Denis wrote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
I suggest that you complain to, say, some members of
parliament that the Canadian public library system
is far from ideal. Note that networking of public
libraries is a nice idea.
I could but the problem is I have stuff todo. ......
Spend some quarter of an hour and lots of your countrymen
(and even you yourself) might get benefits from that.
You don't think I spend time on my LT projects? I'm doing my bit in my own
way.
Tom |
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| Mok-Kong Shen |
| Posted: Thu Dec 25, 2003 10:07 am |
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Tom St Denis wrote:
Quote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
Spend some quarter of an hour and lots of your countrymen
(and even you yourself) might get benefits from that.
You don't think I spend time on my LT projects? I'm doing my bit in my own
way.
It's a matter of 'global' optimization. If you are not
spending every minute available on that project (which
you seemingly aren't), then eventually having a better
public library system is likely worth much more personally
than what occassionally comes out from a usenet discussion
in my humble view.
M. K. Shen |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 10:58 am |
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"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote in message
news:3FEAFD3D.96A8409@t-online.de...
Quote:
Tom St Denis wrote:
"Mok-Kong Shen" <mok-kong.shen@t-online.de> wrote:
Spend some quarter of an hour and lots of your countrymen
(and even you yourself) might get benefits from that.
You don't think I spend time on my LT projects? I'm doing my bit in my
own
way.
It's a matter of 'global' optimization. If you are not
spending every minute available on that project (which
you seemingly aren't), then eventually having a better
public library system is likely worth much more personally
than what occassionally comes out from a usenet discussion
in my humble view.
I don't spend every waking minute working on LT projects because I'm still
in school. I have to also work to pay bills and of course i need time to
relax [re: play games].
The fact that I was working on my OMAC code on christmas day kinda shows I
got a bit of dedication to the project [cuz it's fun].
Tom |
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| Douglas A. Gwyn |
| Posted: Thu Dec 25, 2003 11:26 am |
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"Tom St Denis" <tomstdenis@iahu.ca> wrote...
Quote: might as well be as insightful as Gwyn and suggest the poster go out and
buy
Knuth just to learn division.
That's not what I said. |
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| Tom St Denis |
| Posted: Thu Dec 25, 2003 11:49 am |
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"Douglas A. Gwyn" <DAGwyn@null.net> wrote in message
news:bsf33d$8vs$1@ngspool-d02.news.aol.com...
Quote: "Tom St Denis" <tomstdenis@iahu.ca> wrote...
might as well be as insightful as Gwyn and suggest the poster go out and
buy
Knuth just to learn division.
That's not what I said.
No you said
"Look up "multiple precision arithmetic" in any decent text on algorithms,
for example Kunth's "The Art of Computer Programming"."
Where Knuth [sp corrected] TAOCP is a COMMERCIAL product [each volume cost
about 65$ CDN].
Compared to say HAC which is freely available on the web [or even say the
LTM textbook].
Your post was not insightful at all. I mod you -1,overrated.
Tom |
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