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Search: Posts Made By: dave_dm
Forum: Math 2005-09-23, 17:31
Replies: 61
Views: 4,481
Posted By dave_dm
It's hard to determine the asymptotic proportion...

It's hard to determine the asymptotic proportion of primes generated by any polynomial, ignoring trivial cases. The f(n) = n case is bad enough (the answer being the Prime Number Theorem).

The...
Forum: Hardware 2005-08-04, 10:25
Replies: 1
Views: 1,098
Posted By dave_dm
Tom Crispin from Centaur Technology emailed the...

Tom Crispin from Centaur Technology emailed the gmp-devel list in December asking for help with adding this feature to gmp.



Dave
Forum: Lounge 2005-08-03, 21:56
Replies: 4,137
Views: 264,871
Posted By dave_dm
http://www.citizensrequired.com

http://www.citizensrequired.com
Forum: Lounge 2005-07-04, 17:57
Replies: 93
Views: 7,053
Posted By dave_dm
I don't have nearly as much detail: ...

I don't have nearly as much detail:

http://maps.google.com/maps?q=oxford,uk&ll=51.745472,-1.215963&spn=0.092139,0.140900&t=k&hl=en

Evidently more Google employees went to Cambridge than Oxford...
Forum: GMP-ECM 2005-06-29, 02:23
Replies: 0
Views: 958
Posted By dave_dm
Appeal for machines

The new gmp-ecm Number-Theoretic-Transform code is now pretty mature but there are still some compilation problems on non-x86 architectures. I'm particularly interested in testing on Sparc and Mac...
Forum: Puzzles 2005-05-29, 21:01
Replies: 46
Views: 1,768
Posted By dave_dm
Ken - I'm sure you can do better than that by...

Ken - I'm sure you can do better than that by using multi-character character constants (e.g. "int x = 'ab';") and the fact that integer arithmetic is done modulo 2^32. Or is it 2^64 on Wacky's mac?...
Forum: Puzzles 2005-05-29, 20:33
Replies: 46
Views: 1,768
Posted By dave_dm
Or we can redefine a builtin. Similar remarks to...

Or we can redefine a builtin. Similar remarks to the above wrt whitespace.

#include <iostream>

int main (int argc, char * const argv[]) {
int answer =
// BEGIN inserted code on the next...
Forum: Puzzles 2005-05-29, 20:20
Replies: 46
Views: 1,768
Posted By dave_dm
Here's another cheeky attempt: #include...

Here's another cheeky attempt:

#include <iostream>

int main (int argc, char * const argv[]) {
int answer =
// BEGIN inserted code on the next line
#define answer false&&0
answer
...
Forum: Puzzles 2005-05-29, 18:42
Replies: 46
Views: 1,768
Posted By dave_dm
The only reason I didn't use 0 is that I didn't...

The only reason I didn't use 0 is that I didn't want to use more than one digit in the answer - I stuck the NULL in with full knowledge it would generate a warning but compile successfully :wink:
...
Forum: Puzzles 2005-05-29, 13:59
Replies: 46
Views: 1,768
Posted By dave_dm
Or for maximum cheekiness: #include...

Or for maximum cheekiness:

#include <iostream>

int main (int argc, char * const argv[]) {
int answer =
// BEGIN inserted code on the next line
0;
#define answer cheat
class {
Forum: Puzzles 2005-05-29, 13:43
Replies: 46
Views: 1,768
Posted By dave_dm
In a similar vein, the following is also (IMO)...

In a similar vein, the following is also (IMO) acceptable, although it won't win any prizes:

#include <iostream>

int main (int argc, char * const argv[]) {
int answer =
// BEGIN...
Forum: Puzzles 2005-05-29, 12:17
Replies: 46
Views: 1,768
Posted By dave_dm
How about this for a digit-free solution? ...

How about this for a digit-free solution?

'.'*'-'-'A'
Since the rules require us to use at least one of the relevant digit, this can easily be modified to

x=0: '.'*'-'-'A'+0
x=1:...
Forum: Homework Help 2005-05-25, 22:17
Replies: 27
Views: 2,559
Posted By dave_dm
You could express any number as |{}|! +...

You could express any number as

|{}|! + |{}|! + ... + |{}|!

where |{}|! = (cardinality of the empty set) factorial = 1

Without this kind of 'cheating' I can get 2005 down to seven 2's, I'd...
Forum: GMP-ECM 2005-04-24, 09:03
Replies: 5
Views: 1,102
Posted By dave_dm
Something I've been thinking about: The...

Something I've been thinking about:

The -treefile option stores the product tree of F on disk; this reduces the memory consumption from O(dF * log(dF) * log(n)) to O(dF * log(n)) at the cost of...
Forum: Math 2005-04-17, 23:32
Replies: 5
Views: 1,231
Posted By dave_dm
The link between prime numbers and the Riemann...

The link between prime numbers and the Riemann hypothesis lies in analytic number theory - indeed the Prime Number Theorem was first proved using complex analysis.

The only book I've read on this...
Forum: Math 2005-04-14, 18:18
Replies: 9
Views: 907
Posted By dave_dm
Is your question the following? Does there...

Is your question the following?

Does there exist a polynomial-time reduction from the problem "Discrete log in GF(p)" to the problem "Discrete log in GF(2^n)" ?

I put the 2^n in there because I...
Forum: Lounge 2005-04-14, 18:09
Replies: 7
Views: 1,911
Posted By dave_dm
"Crab Canon" from Hofstadter's Gödel, Escher,...

"Crab Canon" from Hofstadter's Gödel, Escher, Bach is a goodie - Google to find it online.

Dave
Forum: Programming 2005-04-10, 22:42
Replies: 26
Views: 2,808
Posted By dave_dm
This line is absolutely hideous code! :furious:...

This line is absolutely hideous code! :furious: Why not split it over at least 3 lines? Also:

- Strictly speaking, you need to #include <stdlib.h> for atoi.
- I feel obliged to point out that 2...
Forum: Factoring 2005-04-10, 22:27
Replies: 13
Views: 1,815
Posted By dave_dm
Given how smooth his last factor's group order...

Given how smooth his last factor's group order was, nothing short of

2^2 * 3 * 5 * 7 * 11 * ... * 163 * 167 * 173

would surprise me now :smile:

Dave
Forum: Miscellaneous Math 2005-04-07, 14:45
Replies: 10
Views: 5,270
Posted By dave_dm
Vijay, Such claims are the quintessential...

Vijay,

Such claims are the quintessential form of trolling on maths forums. If you really believe you have a correct proof and you really don't want to share it with the whole world then

1)...
Forum: Programming 2005-04-07, 14:14
Replies: 7
Views: 4,339
Posted By dave_dm
Sorry, I don't have a windows machine so I can't...

Sorry, I don't have a windows machine so I can't walk you through this. Search the forums for "gmp" and "cygwin", it's been done. Btw it's quicker to type "cygwin" into google than post "I'm not sure...
Forum: Programming 2005-04-07, 13:12
Replies: 7
Views: 4,339
Posted By dave_dm
Btw if you only need a few values then use the...

Btw if you only need a few values then use the applet at www.swox.com/gmp. If you're only interested in the source then look at mpz/fac_ui.c in the gmp distribution.

Dave
Forum: Programming 2005-04-07, 13:10
Replies: 7
Views: 4,339
Posted By dave_dm
A possible fac.c to print the factorial of the...

A possible fac.c to print the factorial of the first command-line argument:
#include <stdio.h>
#include <gmp.h>

int main (int argc, char **argv)
{
mpz_t x;

mpz_init (x);
...
Forum: Factoring 2005-04-07, 10:25
Replies: 11
Views: 1,716
Posted By dave_dm
Whooooa! Nice one Bruce :) *recreates RSA...

Whooooa! Nice one Bruce :)

*recreates RSA modulus to be 20 digits larger*

Dave
Forum: Factoring 2005-03-14, 08:54
Replies: 2
Views: 647
Posted By dave_dm
Moved to parent forum Factoring (thread not...

Moved to parent forum Factoring (thread not related to GMP-ECM).
Showing results 1 to 25 of 80

 
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