Am 06.08.2011 22:23, schrieb mukesh tiwari:
There are several algorithms mentioned on that page. Do you need the
diameter, width, or something else?
Oh , I did not realize that .Actually first i implemented diameter
algorithm [ http://hpaste.org/49925 ] and tested it on couple of test
cases . Its working fine then i tried to implement " The minimum area
enclosing rectangle for a convex polygon" using four calipers but i
don't know whats wrong code.
Do you have some example data and what wrong result you get?
For any test input [ which i tried ] it outputs 4 . If its implemented
correctly then it will accepted here with slight modification [
http://www.spoj.pl/problems/WLOO0707 ] since it asks for square area.
Couple of test cases which i tried .
ghci>final [ P 1 1 , P 2 2 , P 0 100 , P 0 1 ]
Loading package array-0.3.0.0 ... linking ... done.
Loading package bytestring-0.9.1.5 ... linking ... done.
4.0
ghci>final [ P 0 0 ,P 5 1 , P 9 2 , P 12 3 , P 14 4 , P 15 5 , P 16
7 , P 17 10 , P 18 14 , P 19 19 ]
3.9999999999999982
ghci>final [ P 2 ( -3 ) , P (-1 ) 2 , P 0 5 , P (-5) (-1) , P (-4)
( 2 ) , P 4 0 , P 1 3 , P 4 3 , P (-3) (-4) , P 0 (-2)]
4.0
Thank you
Mukesh Tiwari
I found the error!
In
> width = distVec cpa' cpb'
> length = distVec cqa' cqb'
the length of the direction vectors is used to compute the area and the
area is then always 4.
Replace it with
> width = distVec (V x1 y1) (V x3 y3)
> length = distVec (V x5 y5) (V x7 y7)
and it seems to work:
ghci> final [ P 1 1 , P 2 2 , P 0 100 , P 0 1 ]
221.3707297724792
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