Page 2 - Algorithms Forum?

Dev Shed Forums Sponsor:

#16

January 11th, 2002, 07:25 AM

andnaess

Contributing User

Dev Shed Intermediate (1500 - 1999 posts)

Join Date: Jul 2001

Location: Oslo

Posts: 1,516

Time spent in forums: < 1 sec
Reputation Power: 13

There should be a forum for regular expressions containing one post, and it should read: "Are you absolutely sure you need a regular expression?".

__________________
--
Regards
André Næss

Puritanism: The haunting fear that someone, somewhere may be having fun

#17

January 11th, 2002, 09:59 AM

Thrasher

Canta como rafaé

Join Date: Feb 2001

Location: Barcelona

Posts: 74

Time spent in forums: < 1 sec
Reputation Power: 13

I had the idea of the algorithm forum because of a trouble that I found in my job.

I was developing a system to store logos and ringing tones for mobile phones. The problem came when I was asked to convert to only 2 colors (black and transparent) any image that the user uploaded (in True Color, for example).

Then, searching a lot, I finally found some image dithering techniques which I found very interesting (and useful). And then I thought myself that an algorithms forum would suit for those questions that are not tied to any language.

Note: the function is only 12 lines in C.

I didn't post the question (nor the answer) to any forum because I know that in the PHP forum it would be of no interest to those of "please, give me the result of a query".

It took me to another trouble. Good image resizing. What are bilinear and trilinear filters? And when to use them, before or after the dithering ?

I think most of us have ever had a similar trouble.

__________________
Thrasher

'Y se ahogaron los dooos
No eran duros pa pagar, cuñaaoo !!'
El vagamundo - El risitas y su cuñao

#18

January 11th, 2002, 02:56 PM

andnaess

Contributing User

Join Date: Jul 2001

Location: Oslo

Posts: 1,516

Time spent in forums: < 1 sec
Reputation Power: 13

It sounds like you should pick up a book on image manipulation. Bear in mind though that 12 lines of code in C can still run extremely slow in PHP. I've mentioned this before, but when I implemented the quicksort algorithm in PHP and compared it's running time to the internal sort() routine (which also uses quicksort), the PHP implementation was in the order of 1000 times slower. Have you had a look at imagemagick? http://www.imagemagick.org/ It's available for PHP I think...

#19

January 16th, 2013, 11:00 PM

psk_002

Registered User

Join Date: Jan 2013

Posts: 1

Time spent in forums: 13 m 43 sec
Reputation Power: 0

writing algorithms

Suppose we have a file of n records which are partially sorted as x1 <= x2 <= x3 <= … <= xm, and xm+1 <= ….. <= xn, is it possible to sort the entire file in time O(n) using only a small fixed amount of additional storage?

#20

January 22nd, 2013, 01:00 AM

DaWei_M

Lord of Dorkness

Dev Shed God 8th Plane (8500 - 8999 posts)

Join Date: Jan 2004

Location: Central New York. Texan via Arizona, out of his element!

Posts: 8,515

Time spent in forums: 4 Weeks 18 h 59 m 31 sec
Warnings Level: 20
Number of bans: 3
Reputation Power: 3268

If I remember correctly, the Software forum used to be called Software and Algorithms. The last time I visited it (years ago) all the threads were asking for someone to tell them how to do iris recognition software.

__________________
Functionality rules and clarity matters; if you can work a little elegance in there, you're stylin'.
If you can't spell "u", "ur", and "ne1", why would I hire you? 300 baud modem? Forget I mentioned it.
DaWei on Pointers Politically Incorrect.

#21

February 2nd, 2013, 05:36 AM

ryansmith1

Registered User

Join Date: Feb 2013

Posts: 8

Time spent in forums: 1 h 13 m 26 sec
Reputation Power: 0

I'v voted for PHP because i have great interest in this language.
I want to become a PHP Developer.

Page 2 - Algorithms Forum?

Developer Shed Advertisers and Affiliates