[Jprogramming] J in 5 minutes

[Martin Saurer]

Raul,

Vijay,

 

Many thanks for your feedback on the 4th J video about steganography.

 

Please note, that at the very end of the video, a download link

for the full source code of the example is provided.

It's not necessary to read the JoJ article or copy source code

from there.

Just download it from:

 

   http://www.datavision-gmbh.ch/downloads/StegDemo.zip

 

The reference to the JoJ article was just a comment.

 

 

 

@Raul

 

I always love to play with different solutions for a problem.

Thanks for your implementations of rgb2int and int2rgb.

 

Your implementation of int2rgb is about 6 times faster than mine :-(

But my implementation of rgb2int is about 6 times faster than yours ;-)

 

Tested using the verb timex and a 2048x1539 bitmap image file.

 

That's why I love J.

 

 

 

Cheers

 

Martin

 

 

 

> This is nice!

> 

> If I may, though, I was looking through your journal of J code, and I just

> itch to make "improvements" to it. It's not that it's nonfunctional or

> anything, and I'm not even sure if my changes make it faster. And I

> certainly have not presented anything with any near your polish - and we

> need polish, while my work has tended to look crude and minimalistic -

> but...

> 

>    int2rgb=: [: <. 256 256 256&#:

>    rgb2int=: [: <.  <mailto:256&#.@(3&{.> 256&#.@(3&{."1)

> 

> You could even make them inverses of one another:

> 

>    int2rgb=: ([: <. 256 256 256&#:)   :.rgb2int

>    rgb2int=: ([: <.  <mailto:256&#.@(3&{.> 256&#.@(3&{."1))  :.int2rgb

> 

> I'm not sure that this is any more readable. Someone new to J but with a

> background in some other computer programming language might be more

> comfortable with your expressions than with mine.

> 

> Anyways, it's probably worth noting - as you have already done, but I

> wanted to emphasize it - that the support code for that video is in the

> Journal of J article you linked.

>