the angle of a straight line drawn between 2 points
Subject: the angle of a straight line drawn between 2 points
From: Adam Majewski
Date: Mon, 28 May 2012 18:22:52 +0200
On 27.05.2012 21:36, Stavros Macrakis wrote:
> Why do this by components?
>Maxima lets you calculate directly with the
> complex quantities:
>
> GiveTurn(q,r) := mod( float( carg(b-a)/(2*%pi) ), 1)
Thx for an answer.
It works. I know that for experts it is obvious but for me it is hard to
get such solution.
Adam
>
> -s
>
> On Sun, May 27, 2012 at 2:51 PM, Adam Majewski <adammaj1 at o2.pl
> <mailto:adammaj1 at o2.pl>> wrote:
>
> Hi,
>
> I need a function which computes the angle of a straight line drawn
> between 2 points.
> It should give result in turns ( from 0 to 1 ).
> I have made a function :
>
>
> GiveTurn
>
> and some tests for it.
>
> It gives expected results. Can I as for an opinion of experts ?
>
>
> TIA
>
>
> Adam
>
>
>
> ==== code ==========================
>
>
> kill(all);
>
>
>
> /*
> Determines the angle of a straight line drawn between point one
> and two.
> The number returned, which is a double in degrees, tells us how
> much we have to rotate a horizontal line clockwise for it to match
> the line between the two points.
>
> http://codeforeverything.__wikidot.com/get-angle-of-line-__between-two-points
> <http://codeforeverything.wikidot.com/get-angle-of-line-between-two-points>;
>
> */
>
>
>
> GiveTurn(z3,z4):=(dx:realpart(__z4)-realpart(z3),
> dy:imagpart(z4)-imagpart(z3),
> b:atan2(dy,dx),
> if (b<0) then b:b+2*%pi else b,
> float(b/(2*%pi)));
>
>
>
> compile(all)$
>
> GiveTurn(0, 1+0*%i);
> GiveTurn(0, 1+1*%i);
> GiveTurn(0, 0+1*%i);
> GiveTurn(0,-1+1*%i);
> GiveTurn(0,-1+0*%i);
> GiveTurn(0,-1-1*%i);
> GiveTurn(0, 0-1*%i);
> GiveTurn(0, 1-1*%i);
>
>
>
>
>
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