Mercurial > repos > non-riemannian-opt / file comparison
comparison: src/dist.rs
src/dist.rs
- changeset 17
- ad68dacabe4f
- parent 13
- f67949050a32
- child 53
- 60928f1440e0
equal
deleted
inserted
replaced
| 16:a6efe0fafd90 | 17:ad68dacabe4f |
|---|---|
| 1 /*! | 1 /*! |
| 2 Implementations of the distance function and the distance function squared, on manifolds. | 2 Implementations of the distance function and the distance function squared, on manifolds. |
| 3 */ | 3 */ |
| 4 | 4 |
| 5 use alg_tools::mapping::Apply; | 5 use alg_tools::mapping::Apply; |
| 6 use alg_tools::euclidean::Euclidean; | |
| 6 use crate::manifold::ManifoldPoint; | 7 use crate::manifold::ManifoldPoint; |
| 7 use crate::fb::{Grad, Desc}; | 8 use crate::fb::{Grad, Desc, Prox}; |
| 8 | 9 |
| 9 /// Structure for distance-to functions | 10 /// Structure for distance-to functions |
| 10 pub struct DistTo<M : ManifoldPoint>(pub M); | 11 pub struct DistTo<M : ManifoldPoint>(pub M); |
| 11 | 12 |
| 12 impl<M : ManifoldPoint> Apply<M> for DistTo<M> { | 13 impl<M : ManifoldPoint> Apply<M> for DistTo<M> { |
| 56 impl<M : ManifoldPoint> Grad<M> for DistToSquaredDiv2<M> { | 57 impl<M : ManifoldPoint> Grad<M> for DistToSquaredDiv2<M> { |
| 57 fn grad(&self, x : &M) -> M::Tangent { | 58 fn grad(&self, x : &M) -> M::Tangent { |
| 58 x.log(&self.0) | 59 x.log(&self.0) |
| 59 } | 60 } |
| 60 } | 61 } |
| 62 | |
| 63 impl<M : ManifoldPoint> Prox<M> for DistTo<M> { | |
| 64 /// This is proximal map is a type of soft-thresholding on manifolds. | |
| 65 fn prox(&self, τ : f64, x : M) -> M { | |
| 66 let v = x.log(&self.0); | |
| 67 let d = v.norm2(); | |
| 68 if d <= τ { | |
| 69 self.0.clone() | |
| 70 } else { | |
| 71 x.exp( &(v * (τ / d)) ) | |
| 72 } | |
| 73 } | |
| 74 } |
