Copyright | (C) 2012-2015 Edward Kmett |
---|---|
License | BSD-style (see the file LICENSE) |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | Trustworthy |
Language | Haskell98 |
Plücker coordinates for lines in 3d homogeneous space.
- data Plucker a = Plucker !a !a !a !a !a !a
- squaredError :: (Eq a, Num a) => Plucker a -> a
- isotropic :: Epsilon a => Plucker a -> Bool
- (><) :: Num a => Plucker a -> Plucker a -> a
- plucker :: Num a => V4 a -> V4 a -> Plucker a
- plucker3D :: Num a => V3 a -> V3 a -> Plucker a
- parallel :: Epsilon a => Plucker a -> Plucker a -> Bool
- intersects :: (Epsilon a, Ord a) => Plucker a -> Plucker a -> Bool
- data LinePass
- passes :: (Epsilon a, Num a, Ord a) => Plucker a -> Plucker a -> LinePass
- quadranceToOrigin :: Fractional a => Plucker a -> a
- closestToOrigin :: Fractional a => Plucker a -> V3 a
- isLine :: Epsilon a => Plucker a -> Bool
- coincides :: (Epsilon a, Fractional a) => Plucker a -> Plucker a -> Bool
- coincides' :: (Epsilon a, Fractional a, Ord a) => Plucker a -> Plucker a -> Bool
- p01 :: Lens' (Plucker a) a
- p02 :: Lens' (Plucker a) a
- p03 :: Lens' (Plucker a) a
- p10 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- p12 :: Lens' (Plucker a) a
- p13 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- p20 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- p21 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- p23 :: Lens' (Plucker a) a
- p30 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- p31 :: Lens' (Plucker a) a
- p32 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a)
- e01 :: E Plucker
- e02 :: E Plucker
- e03 :: E Plucker
- e12 :: E Plucker
- e31 :: E Plucker
- e23 :: E Plucker
Documentation
Plücker coordinates for lines in a 3-dimensional space.
Plucker !a !a !a !a !a !a |
squaredError :: (Eq a, Num a) => Plucker a -> a Source
Valid Plücker coordinates p
will have squaredError
p ==
0
That said, floating point makes a mockery of this claim, so you may want to use nearZero
.
isotropic :: Epsilon a => Plucker a -> Bool Source
Checks if the line is near-isotropic (isotropic vectors in this quadratic space represent lines in real 3d space).
(><) :: Num a => Plucker a -> Plucker a -> a infixl 5 Source
This isn't th actual metric because this bilinear form gives rise to an isotropic quadratic space
plucker :: Num a => V4 a -> V4 a -> Plucker a Source
Given a pair of points represented by homogeneous coordinates generate Plücker coordinates for the line through them, directed from the second towards the first.
plucker3D :: Num a => V3 a -> V3 a -> Plucker a Source
Given a pair of 3D points, generate Plücker coordinates for the line through them, directed from the second towards the first.
Operations on lines
intersects :: (Epsilon a, Ord a) => Plucker a -> Plucker a -> Bool Source
Checks if two lines intersect (or nearly intersect).
Describe how two lines pass each other.
Coplanar | The lines are coplanar (parallel or intersecting). |
Clockwise | The lines pass each other clockwise (right-handed screw) |
Counterclockwise | The lines pass each other counterclockwise (left-handed screw). |
passes :: (Epsilon a, Num a, Ord a) => Plucker a -> Plucker a -> LinePass Source
Check how two lines pass each other. passes l1 l2
describes
l2
when looking down l1
.
quadranceToOrigin :: Fractional a => Plucker a -> a Source
The minimum squared distance of a line from the origin.
closestToOrigin :: Fractional a => Plucker a -> V3 a Source
The point where a line is closest to the origin.
isLine :: Epsilon a => Plucker a -> Bool Source
Not all 6-dimensional points correspond to a line in 3D. This predicate tests that a Plücker coordinate lies on the Grassmann manifold, and does indeed represent a 3D line.
coincides :: (Epsilon a, Fractional a) => Plucker a -> Plucker a -> Bool Source
Checks if two lines coincide in space. In other words, undirected equality.
coincides' :: (Epsilon a, Fractional a, Ord a) => Plucker a -> Plucker a -> Bool Source
Checks if two lines coincide in space, and have the same orientation.
Basis elements
p10 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a
p13 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a
p20 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a
p21 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a
p30 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a
p32 :: (Functor f, Num a) => (a -> f a) -> Plucker a -> f (Plucker a) Source
These elements form an alternate basis for the Plücker space, or the Grassmanian manifold Gr(2,V4)
.
p10
::Num
a =>Lens'
(Plucker
a) ap20
::Num
a =>Lens'
(Plucker
a) ap30
::Num
a =>Lens'
(Plucker
a) ap32
::Num
a =>Lens'
(Plucker
a) ap13
::Num
a =>Lens'
(Plucker
a) ap21
::Num
a =>Lens'
(Plucker
a) a