module Complex ( Complex((:+)), realPart, imagPart, conjugate, mkPolar, cis, polar, magnitude, phase ) where infix 6 :+ data (RealFloat a) => Complex a = !a :+ !a realPart, imagPart :: (RealFloat a) => Complex a -> a conjugate :: (RealFloat a) => Complex a -> Complex a mkPolar :: (RealFloat a) => a -> a -> Complex a cis :: (RealFloat a) => a -> Complex a polar :: (RealFloat a) => Complex a -> (a,a) magnitude, phase :: (RealFloat a) => Complex a -> a instance (RealFloat a) => Eq (Complex a) where ... instance (RealFloat a) => Read (Complex a) where ... instance (RealFloat a) => Show (Complex a) where ... instance (RealFloat a) => Num (Complex a) where ... instance (RealFloat a) => Fractional (Complex a) where ... instance (RealFloat a) => Floating (Complex a) where ... |
Complex numbers are an algebraic type. The constructor (:+) forms a complex number from its real and imaginary rectangular components. This constructor is strict: if either the real part or the imaginary part of the number is bottom, the entire number is bottom. A complex number may also be formed from polar components of magnitude and phase by the function mkPolar. The function cis produces a complex number from an angle t. Put another way, cis t is a complex value with magnitude 1 and phase t (modulo 2pi).
The function polar takes a complex number and returns a (magnitude, phase) pair in canonical form: The magnitude is nonnegative, and the phase, in the range (- pi , pi ]; if the magnitude is zero, then so is the phase.
The functions realPart and imagPart extract the rectangular components of a complex number and the functions magnitude and phase extract the polar coordinates of a complex number. Also defined on complex numbers is the conjugate function conjugate.
The magnitude and sign of a complex number are defined as follows:
abs z = magnitude z :+ 0 signum 0 = 0 signum z@(x:+y) = x/r :+ y/r where r = magnitude zThat is, abs z is a number with the magnitude of z, but oriented in the positive real direction, whereas signum z has the phase of z, but unit magnitude. (abs for a complex number differs from magnitude only in type.)
module Complex(Complex((:+)), readPart, imagPart, conjugate, mkPolar, cis, polar, magnitude, phase) where
infix 6 :+
data (RealFloat a) => Complex a = !a :+ !a deriving (Eq,Read,Show)
realPart, imagPart :: (RealFloat a) => Complex a -> a realPart (x:+y) = x imagPart (x:+y) = y
conjugate :: (RealFloat a) => Complex a -> Complex a conjugate (x:+y) = x :+ (-y)
mkPolar :: (RealFloat a) => a -> a -> Complex a mkPolar r theta = r * cos theta :+ r * sin theta
cis :: (RealFloat a) => a -> Complex a cis theta = cos theta :+ sin theta
polar :: (RealFloat a) => Complex a -> (a,a) polar z = (magnitude z, phase z)
magnitude, phase :: (RealFloat a) => Complex a -> a magnitude (x:+y) = scaleFloat k (sqrt ((scaleFloat mk x)^2 + (scaleFloat mk y)^2)) where k = max (exponent x) (exponent y) mk = - k
phase (x:+y) = atan2 y x
instance (RealFloat a) => Num (Complex a) where (x:+y) + (x':+y') = (x+x') :+ (y+y') (x:+y) - (x':+y') = (x-x') :+ (y-y') (x:+y) * (x':+y') = (x*x'-y*y') :+ (x*y'+y*x') negate (x:+y) = negate x :+ negate y abs z = magnitude z :+ 0 signum 0 = 0 signum z@(x:+y) = x/r :+ y/r where r = magnitude z fromInteger n = fromInteger n :+ 0
instance (RealFloat a) => Fractional (Complex a) where (x:+y) / (x':+y') = (x*x''+y*y'') / d :+ (y*x''-x*y'') / d where x'' = scaleFloat k x' y'' = scaleFloat k y' k = - max (exponent x') (exponent y') d = x'*x'' + y'*y'' fromRational a = fromRational a :+ 0
instance (RealFloat a) => Floating (Complex a) where pi = pi :+ 0 exp (x:+y) = expx * cos y :+ expx * sin y where expx = exp x log z = log (magnitude z) :+ phase z sqrt 0 = 0 sqrt z@(x:+y) = u :+ (if y < 0 then -v else v) where (u,v) = if x < 0 then (v',u') else (u',v') v' = abs y / (u'*2) u' = sqrt ((magnitude z + abs x) / 2) sin (x:+y) = sin x * cosh y :+ cos x * sinh y cos (x:+y) = cos x * cosh y :+ (- sin x * sinh y) tan (x:+y) = (sinx*coshy:+cosx*sinhy)/(cosx*coshy:+(-sinx*sinhy)) where sinx = sin x cosx = cos x sinhy = sinh y coshy = cosh y sinh (x:+y) = cos y * sinh x :+ sin y * cosh x cosh (x:+y) = cos y * cosh x :+ sin y * sinh x tanh (x:+y) = (cosy*sinhx:+siny*coshx)/(cosy*coshx:+siny*sinhx) where siny = sin y cosy = cos y sinhx = sinh x coshx = cosh x asin z@(x:+y) = y':+(-x') where (x':+y') = log ((-y:+x) + sqrt (1 - z*z)) acos z@(x:+y) = y'':+(-x'') where (x'':+y'') = log (z + ((-y'):+x')) (x':+y') = sqrt (1 - z*z) atan z@(x:+y) = y':+(-x') where (x':+y') = log (((1-y):+x) / sqrt (1+z*z)) asinh z = log (z + sqrt (1+z*z)) acosh z = log (z + (z+1) * sqrt ((z-1)/(z+1))) atanh z = log ((1+z) / sqrt (1-z*z))