OpenEuphoria

Re: FIND THE TRUE TAN WITHIN A CIRCLE

• Posted by "Carl R. White" <C.R.White at SCM.BRAD.AC.UK> Mar 23, 1999
• 564 views

On Mon, 22 Mar 1999 RodDamon at AOL.COM wrote:

] constant Pi=3.14159265359 --- Now in version 2.1
]
] global function Sgn(atom x)
]         if x>0 then
]                 return 1
]         elsif x<0 then
]                 return -1
]         else
]                 return 0
]         end if
] end function
]
] global function arctan2(atom Y, atom X)
]         return
] abs(-arctan(X/(Y+(Y=0)))*-(Y!=0)-(Pi*.5)*Sgn(X)*-(Y=0)+Pi*-(Y<0)*(-(X>=0)+(X<0
] ))+(-Pi*2)*-(X<0))
]
] WHERE X & Y ARE:
]
]                                    +Y
]                                      I
]                                      I
]                          -X -------------- +X
]                                      I
]                                      I
]                                    -Y

I attempted to simplify your code, but something doesn't seem right...

global function arctan2(atom y, atom x)
  integer yeo, ylo, xlo -- conditions
  yeo = (y = 0) -- I hope the names are obvious enough :)
  ylo = (y < 0)
  xlo = (x < 0)

  return abs( -- you haven't defined abs() but I think we all know what
              -- it means :)... Are you sure all answers should be +ve?

    -- Calculation block:
    -- Result Section     * Condition Section

    + arctan( x/(y+yeo) ) * (1-yeo)          -- note the unary '+'

    + Sgn(X)*(Pi/2)       * yeo

    + Pi                  * ylo * (1-2*xlo)

    + 2*Pi                * xlo

  )
end function

I can cope with obfuscated shortest-Euphoria code, in fact I'm a great
lover of it (I did similar things in Commodore BASIC many moons ago) but
not at the level you showed in your example! Ooh, my head hurts :)

Carl

PS Nice work by the way...

--
Carl R White -- cyrek- at -bigfoot.com -- http://www.bigfoot.com/~cyrek
 aka Cyrek   --    No hyphens :)    --       Bigfoot URL Alias