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worldhits
r4wp4
r3wp18
total:22

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world-name: r4wp

Group: #Red ... Red language group [web-public]
PeterWood:
14-Aug-2012
It wouldn't take long to add addition and multiplication if that 
would help.
Arnold:
28-Jul-2013
(Because of the multiplication factor used a small difference in 
startvalue will result in completely incomparable resulting numbers)
Arnold:
30-Jul-2013
(My) Conclusion the multiplication by 1664525 causes the results 
of the C source and Red/System source to diverge, possible reason 
calculation with long integers in C versus integer calculation in 
Red/System troubled by overflows.
Kaj:
30-Jul-2013
It must be 64 bit, because a long on Mac would probably be 84 bit 
there. Indeed, your multiplication result is 64 bit, so on Red/System, 
it is wrapping around

world-name: r3wp

Group: Core ... Discuss core issues [web-public]
Ashley:
19-Apr-2010
re:Python's operators. I've always liked AutoIT's assignment operators, 
some of which (especially concatenantion) would be quite useful in 
REBOL.

	=	Assignment. e.g. $var = 5ΚΚΚΚ (assigns the number 5 to $var)
	+=	Addition assignment. e.g. $var += 1 ΚΚΚ (adds 1 to $var)
	-=	Subtraction assignment.
	*=	Multiplication assignment.
	/=	Division assignment.

 &=	Concatenation assignment.Κ e.g. $var = "one", and then $var &= 
 10ΚΚΚ ($var now equals "one10")
BrianH:
25-Jun-2010
You are missing a multiplication.
BrianH:
25-Jun-2010
Unless you want all numeric operations on the percent! type to include 
implicit multiplication.
BrianH:
25-Jun-2010
Yes, but he told  to add 50% of what to 10? That's the missing multiplication.
Ladislav:
14-Jul-2010
But, the principle is quite simple: multiply the number by a "suitable" 
power of 10 and convert the result to integer. The trouble is, that 
you need to use a high precision multiplication and power.
Pavel:
17-Jul-2010
When trying to code D.J.Bernstein hashing function: forall key [hash: 
hash * 33 xor first key] I found that this simple notation is faster 
than traditional C like: forall key [hash: xor~ add shift hash 5 
hash first key]. (Note for real use it is necessary to shrink hash 
to 4 bytes.) seems shift and additioin is not faster than multiplication 
under Rebol?
Group: Parse ... Discussion of PARSE dialect [web-public]
Geocaching:
15-Mar-2011
Ladislav... according to wiki, addition, subtraction, multiplication 
and division are left-assiciative... http://en.wikipedia.org/wiki/Operator_associativity
Group: AGG ... to discus new Rebol/View with AGG [web-public]
Tomc:
23-Feb-2005
so how about matrix multiplication and transpose -- non-graphics 
specialized maths
Group: SVG Renderer ... SVG rendering in Draw AGG [web-public]
Steeve:
10-Oct-2009
Currently my problem is with the linear gradients when a matrix operation 
is applied on them.


The linear gradient use a vector v = (x1, y1) - (x2, y2) to indicate 
his direction and length.


grad-pen is defined like this:  [grad-pen linear normal xy 0 len 
angle [... stop colors]]

And i calculate his values with:

- xy = (x1,y1)
- len =  length of the vector v 
- the angle of the vector v


When a matrix is associated with the gradient, i multiply the coordinates 
of the vector v by the matrix before calculating the other values.
It's working well when the gradient is vertical or horizontal.

But when the gradient is inclined , the matrix multiplication give 
a wrong vector and i don't know why.
Group: rebcode ... Rebcode discussion [web-public]
Ladislav:
14-Oct-2005
binary logarithm: you can spare one multiplication, that doesn't 
look like a big difference
Ladislav:
14-Oct-2005
I think, that everyone knows, that division by a constant can be 
replaced multiplication by its reciprocal, which is a constant too 
:-)
Ladislav:
14-Oct-2005
otherwise you really need some multiplication
Rebolek:
1-Dec-2005
I rewrote my old 3d demo to rebcode to see the speed difference. 
But I found that normal rebol can draw 120+ triangles without slowing 
down and because I became bored adding more objects I stopped testing 
it :) Anyway, rebcode optimalised (just three or four functions - 
matrix multiplication, inversion and 3d to 2d conversion - are rewritten 
to rebcode, it can be optimalized more) version is here - http://krutek.info/rebol/ratrix.r
. z-buffer does not work very well as you can see.
Group: !REBOL3-OLD1 ... [web-public]
Geomol:
11-Apr-2006
We need some different symbols for multiplication. dot-product, cross-product.
Ladislav:
2-Jul-2009
...multiplication may still trigger rounding, though
Ladislav:
2-Jul-2009
that is caused by the multiplication rounding
Ladislav:
2-Jul-2009
another variant would be to generate the uniform deviates in the 
definite interval not allowing multiplication to "mess things"
Group: Red ... Red language group [web-public]
Dockimbel:
13-Apr-2011
Yes, multiplication or division by a power of 2 are generating shifts, 
so the feature is available, the << >> operators are now just syntactic 
sugar, that's why their implementation has been delayed.