World: r3wp

sure, my HP48 can do that easily

as long there is some definable way to convert between them or make 
some sense from it

the acceleration of gravity would be 9.82 [m/s/s] so units themselves 
are math expressions

It that something for a dialect rather then to be inlcuded in the 
core langauge?

peterwood, quite possibly

we already have money datatypes

why not ones for mensuration

I think it's worth making a concept dialect for scientific math with 
units

Hmm, funny idea. To add 6 meters and 2 UK foot:
SIm6 + UKfoot2
Looks weird. :-)

actually, it would be good to make a ctx-unit to handle units exactly 
like the hp48 does

I often have to calculate BMIs .. and most people know their height 
in feet and inches, but their weight in kgs :(

the hp48 uses an underscore to attach the number to a unit: 6_m / 
23_cm

http://www.apple.com/downloads/macosx/math_science/eurekalc.html
<-- I think that could be done with a dialect...

so many things to do!

that calculator needs a spell checker as well!

well, kintetic energy is that new thing, you know...

Graham, I've made a RAMBO proposal for vector and matrix.

how do you find the 4th part of a 4D vector?

ie. what comes after /z ?

4? :)

x, y and z can be possible, like we have first, second ...
To reach the next dimensions, integers are needed.
v: 1.0x2.0x3.0x4.0x5.0
v/x
1.0
v/5
5.0

A quick google took me to the Python page - "The 4th component can 
be accessed either by the name w or t." 

http://cgkit.sourceforge.net/doc2/vec4.html

First, second, ... go up to tenth. We don't have eleventh. You need 
to do serie/11 to get the 11'th element.

It would seem w is the popular choice - www.mathpages.com/home/kmath482.htm

Peter, ok idea, and I'm all for that. There just shouldn't be a limit, 
and we have to use integers to reach later parts of a vector ... 
like with series.

Good to know that is solved.

don't know why we just don't start with "a" and work our way thru 
to "z"

There also seems to be a convention of x y z t u v

We run out of characters giving meaning, if we have for example an 
8-dimensional vector. But it should be possible to make an 8-dimensional 
vector.

t, u and v is probably found a lot in 3D graphics math.

I'm sure that there is a mathematical convention and would be surprised 
if Carl S doesn't know it.

t for translation. u and v is used as uv-mapping of textures.

I don't even think, it'll take up much code to implement these things. 
The theory is there, and it's well-defined, how you calculate with 
vectors and matrices.

All different kinds of 3D manipulation will look simple, like scaling, 
rotation, reflection, etc. All those are well-defined matrix-operations. 
And supporting multi-dimensional vectors and matrices might pull 
a lot of science people to REBOL.

We need some different symbols for multiplication. dot-product, cross-product.

M: make matrix! 4x4
T: make matrix! 4x4
maybe: M x T
:-)

but x might be a word.

maybe
M * T for cross-product, and
M . T for dot-product?

Would it be strange to have dots flying around in the code, all by 
themselves?

Reaching second element on second row in a 2-dimensional matrix:
M/2x2

And of course we should have matrices with more than 2 dimensions, 
so something like this is possible:
M/2x2x2

So pairs need to be extended somehow into a datatype, which is like 
a vector, but with integers instead of decimals.

/joke-mode-on
Sorry guys, REBOL 3.0 is delayed another year! ;-)
/joke-mode-off

Hi! Why use pairs for idexing thats what paths are for. What is wrong 
with M/2/2/2   ?

we should stay with path imo ...

although we got overvoted for rebcode, which uses dot ;-)

since pairs are only integers not decimals vector and matrix could 
be replacement for draw dialect coordinates, AGG has subpixel accuracy

Karol: You can do 2x2 with pair! but not 2/2 with path!

like this: a: [ [ 0 1] [ 2.2 3.1]]  a/2/1

Geomol: "So pairs need to be extended somehow into a datatype, which 
is like a vector, but with integers instead of decimals." --- decimal! 
is better in my opinion. It's consistent with current behaviour whre 
you can do 
>> block/4.5
and decimal part is truncated.

but with matrix we can     a: make matrix! [ [ 0 1] [ 2.2 3.1]]  
a/2/1