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[DPRG] which vector? what vector?
Subject: [DPRG] which vector? what vector?
From: Dale Wheat
dale at dalewheat.com
Date: Sun Apr 27 18:54:08 CDT 2008
Dean,
That's precisely what I mean. I want to make sure I'm using the right terms to
describe what's going on in the code. As Jeff pointed out, they really are
polar coordinates. I just wanted to know what to call them when linked
together, for example, if I created a structure to hold the values returned from
a function.
In the meantime, I broke the calculations up into two distinct functions,
target_angle() and target_distance() and used them separately. I've recoded
this silly thing like ten times already.
Thanks,
Dale Wheat
(972) 486-1317
(877) DALE WHEAT
http://dalewheat.com
Dean Hall wrote:
> "Vector (spatial), an object defined by both magnitude and direction; in
> contrast to a scalar, an object with magnitude only."
> -- http://en.wikipedia.org/wiki/Vector_%28spatial%29
>
> Notice that it says direction. That can be any unit of direction and
> any number of dimensions. In your case you said "distance + angle", so
> "distance" is the magnitude and "angle" is the direction.
>
> However if I were to nit-pick, I would say there is something wrong with
> your sentence. A Cartesian coordinate system means a rectangular
> coordinate system (usually X and Y for 2 dimensions). So a Cartesian
> vector [3, 4] would be a vector that goes +3 in the X direction and +4
> in the Y direction and whose magnitude is 5 and direction is atan(4/3)
> or roughly 53.1 degrees counter-clockwise from the +X axis.
>
> When you tell me you have a vector given as distance + angle. I would
> say you have a vector in polar coordinates; whose variables are usually
> given as [r, theta]. r is the distance, theta is the angle.
>
> One can convert Cartesian to Polar systems and back. Thus the Cartesian
> vector [3, 4] is equivalent to the Polar vector [5, atan(4/3)].
>
> !!Dean
>
>
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