src/measures/delta.rs

changeset 0
eb3c7813b67a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/measures/delta.rs	Thu Dec 01 23:07:35 2022 +0200
@@ -0,0 +1,291 @@
+/*!
+This module implementes delta measures, i.e., single spikes $\alpha \delta_x$ for some
+location $x$ and mass $\alpha$.
+*/
+
+use super::base::*;
+use crate::types::*;
+use std::ops::{Div, Mul, DivAssign, MulAssign, Neg};
+use serde::ser::{Serialize, Serializer, SerializeStruct};
+use alg_tools::norms::{Norm, Dist};
+use alg_tools::linops::{Apply, Linear};
+
+/// Representation of a delta measure.
+///
+/// This is a single spike $\alpha \delta\_x$ for some location $x$ in `Domain` and
+/// a mass $\alpha$ in `F`.
+#[derive(Clone,Copy,Debug)]
+pub struct DeltaMeasure<Domain, F : Num> {
+    // This causes [`csv`] to crash.
+    //#[serde(flatten)]
+    /// Location of the spike
+    pub x : Domain,
+    /// Mass of the spike
+    pub α : F
+}
+
+const COORDINATE_NAMES : &'static [&'static str] = &[
+    "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7"
+];
+
+// Need to manually implement serialisation as [`csv`] writer fails on
+// structs with nested arrays as well as with #[serde(flatten)].
+impl<F : Num, const N : usize> Serialize for DeltaMeasure<Loc<F, N>, F>
+where
+    F: Serialize,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        assert!(N <= COORDINATE_NAMES.len());
+
+        let mut s = serializer.serialize_struct("DeltaMeasure", N+1)?;
+        for (i, e) in (0..).zip(self.x.iter()) {
+            s.serialize_field(COORDINATE_NAMES[i], e)?;
+        }
+        s.serialize_field("weight", &self.α)?;
+        s.end()
+    }
+}
+
+
+impl<Domain : PartialEq, F : Float> Measure<F> for DeltaMeasure<Domain, F> {
+    type Domain = Domain;
+}
+
+impl<Domain : PartialEq, F : Float> Norm<F, Radon> for DeltaMeasure<Domain, F> {
+    #[inline]
+    fn norm(&self, _ : Radon) -> F {
+        self.α.abs()
+    }
+}
+
+impl<Domain : PartialEq, F : Float> Dist<F, Radon> for DeltaMeasure<Domain, F> {
+    #[inline]
+    fn dist(&self, other : &Self, _ : Radon) -> F {
+        if self.x == other. x {
+            (self.α - other.α).abs()
+        } else {
+            self.α.abs() + other.α.abs()
+        }
+    }
+}
+
+impl<'b, Domain, G, F : Num, V : Mul<F, Output=V>> Apply<G> for DeltaMeasure<Domain, F>
+where G: for<'a> Apply<&'a Domain, Output = V>,
+      V : Mul<F> {
+    type Output = V;
+
+    #[inline]
+    fn apply(&self, g : G) -> Self::Output {
+        g.apply(&self.x) * self.α
+    }
+}
+
+impl<Domain, G, F : Num, V : Mul<F, Output=V>> Linear<G> for DeltaMeasure<Domain, F>
+where G: for<'a> Apply<&'a Domain, Output = V> {
+    type Codomain = V;
+}
+
+// /// Partial blanket implementation of [`DeltaMeasure`] as a linear functional of [`Mapping`]s.
+// /// A full blanket implementation is not possible due to annoying Rust limitations: only [`Apply`]
+// /// on a reference is implemented, but a consuming [`Apply`] has to be implemented on a case-by-case
+// /// basis, not because an implementation could not be written, but because the Rust trait system
+// /// chokes up.
+// impl<Domain, G, F : Num, V> Linear<G> for DeltaMeasure<Domain, F>
+// where G: for<'a> Apply<&'a Domain, Output = V>,
+//       V : Mul<F>,
+//       Self: Apply<G, Output =  <V as Mul<F>>::Output> {
+//     type Codomain = <V as Mul<F>>::Output;
+// }
+
+// impl<'b, Domain, G, F : Num, V> Apply<&'b G> for DeltaMeasure<Domain, F>
+// where G: for<'a> Apply<&'a Domain, Output = V>,
+//       V : Mul<F> {
+//     type Output = <V as Mul<F>>::Output;
+
+//     #[inline]
+//     fn apply(&self, g : &'b G) -> Self::Output {
+//         g.apply(&self.x) * self.α
+//     }
+// }
+
+// /// Implementation of the necessary apply for BTFNs
+// mod btfn_apply {
+//     use super::*;
+//     use alg_tools::bisection_tree::{BTFN, BTImpl, SupportGenerator, LocalAnalysis};
+
+//     impl<F : Float, BT, G, V, const N : usize> Apply<BTFN<F, G, BT, N>>
+//     for DeltaMeasure<Loc<F, N>, F>
+//     where BT : BTImpl<F, N>,
+//         G : SupportGenerator<F, N, Id=BT::Data>,
+//         G::SupportType : LocalAnalysis<F, BT::Agg, N> + for<'a> Apply<&'a Loc<F, N>, Output = V>,
+//         V : std::iter::Sum + Mul<F> {
+        
+//         type Output = <V as Mul<F>>::Output;
+
+//         #[inline]
+//         fn apply(&self, g : BTFN<F, G, BT, N>) -> Self::Output {
+//             g.apply(&self.x) * self.α
+//         }
+//     }
+// }
+
+
+impl<D, Domain, F : Num> From<(D, F)> for DeltaMeasure<Domain, F>
+where D : Into<Domain> {
+    #[inline]
+    fn from((x, α) : (D, F)) -> Self {
+        DeltaMeasure{x: x.into(), α: α}
+    }
+}
+
+/*impl<F : Num> From<(F, F)> for DeltaMeasure<Loc<F, 1>, F> {
+    #[inline]
+    fn from((x, α) : (F, F)) -> Self {
+        DeltaMeasure{x: Loc([x]), α: α}
+    }
+}*/
+
+impl<Domain, F : Num> DeltaMeasure<Domain, F> {
+    /// Set the mass of the spike.
+    #[inline]
+    pub fn set_mass(&mut self, α : F) {
+        self.α = α
+    }
+
+    /// Set the location of the spike.
+    #[inline]
+    pub fn set_location(&mut self, x : Domain) {
+        self.x = x
+    }
+
+    /// Get the mass of the spike.
+    #[inline]
+    pub fn get_mass(&self) -> F {
+        self.α
+    }
+
+    /// Get a mutable reference to the mass of the spike.
+    #[inline]
+    pub fn get_mass_mut(&mut self) -> &mut F {
+        &mut self.α
+    }
+
+    /// Get a reference to the location of the spike.
+    #[inline]
+    pub fn get_location(&self) -> &Domain {
+        &self.x
+    }
+
+    /// Get a mutable reference to the location of the spike.
+    #[inline]
+    pub fn get_location_mut(&mut self) -> &mut Domain {
+        &mut self.x
+    }
+}
+
+
+macro_rules! make_delta_scalarop_rhs {
+    ($trait:ident, $fn:ident, $trait_assign:ident, $fn_assign:ident) => {
+        impl<F : Num, Domain> $trait<F> for DeltaMeasure<Domain, F> {
+            type Output = Self;
+            fn $fn(mut self, b : F) -> Self {
+                self.α.$fn_assign(b);
+                self
+            }
+        }
+
+        impl<'a, F : Num, Domain> $trait<&'a F> for DeltaMeasure<Domain, F> {
+            type Output = Self;
+            fn $fn(mut self, b : &'a F) -> Self {
+                self.α.$fn_assign(*b);
+                self
+            }
+        }
+
+        impl<'b, F : Num, Domain : Clone> $trait<F> for &'b DeltaMeasure<Domain, F> {
+            type Output = DeltaMeasure<Domain, F>;
+            fn $fn(self, b : F) -> Self::Output {
+                DeltaMeasure { α : self.α.$fn(b), x : self.x.clone() }
+            }
+        }
+
+        impl<'a, 'b, F : Num, Domain : Clone> $trait<&'a F> for &'b DeltaMeasure<Domain, F> {
+            type Output = DeltaMeasure<Domain, F>;
+            fn $fn(self, b : &'a F) -> Self::Output {
+                DeltaMeasure { α : self.α.$fn(*b), x : self.x.clone() }
+            }
+        }
+
+        impl<F : Num, Domain> $trait_assign<F> for DeltaMeasure<Domain, F> {
+            fn $fn_assign(&mut self, b : F) {
+                self.α.$fn_assign(b)
+            }
+        }
+
+        impl<'a, F : Num, Domain> $trait_assign<&'a F> for DeltaMeasure<Domain, F> {
+            fn $fn_assign(&mut self, b : &'a F) {
+                self.α.$fn_assign(*b)
+            }
+        }
+    }
+}
+
+make_delta_scalarop_rhs!(Mul, mul, MulAssign, mul_assign);
+make_delta_scalarop_rhs!(Div, div, DivAssign, div_assign);
+
+macro_rules! make_delta_scalarop_lhs {
+    ($trait:ident, $fn:ident; $($f:ident)+) => { $(
+        impl<Domain> $trait<DeltaMeasure<Domain, $f>> for $f {
+            type Output = DeltaMeasure<Domain, $f>;
+            fn $fn(self, mut δ : DeltaMeasure<Domain, $f>) -> Self::Output {
+                δ.α = self.$fn(δ.α);
+                δ
+            }
+        }
+
+        impl<'a, Domain : Clone> $trait<&'a DeltaMeasure<Domain, $f>> for $f {
+            type Output = DeltaMeasure<Domain, $f>;
+            fn $fn(self, δ : &'a DeltaMeasure<Domain, $f>) -> Self::Output {
+                DeltaMeasure{ x : δ.x.clone(), α : self.$fn(δ.α) }
+            }
+        }
+
+        impl<'b, Domain> $trait<DeltaMeasure<Domain, $f>> for &'b $f {
+            type Output = DeltaMeasure<Domain, $f>;
+            fn $fn(self, mut δ : DeltaMeasure<Domain, $f>) -> Self::Output {
+                δ.α = self.$fn(δ.α);
+                δ
+            }
+        }
+
+        impl<'a, 'b, Domain : Clone> $trait<&'a DeltaMeasure<Domain, $f>> for &'b $f {
+            type Output = DeltaMeasure<Domain, $f>;
+            fn $fn(self, δ : &'a DeltaMeasure<Domain, $f>) -> Self::Output {
+                DeltaMeasure{ x : δ.x.clone(), α : self.$fn(δ.α) }
+            }
+        }
+    )+ }
+}
+
+make_delta_scalarop_lhs!(Mul, mul; f32 f64 i8 i16 i32 i64 isize u8 u16 u32 u64 usize);
+make_delta_scalarop_lhs!(Div, div; f32 f64 i8 i16 i32 i64 isize u8 u16 u32 u64 usize);
+
+macro_rules! make_delta_unary {
+    ($trait:ident, $fn:ident, $type:ty) => {
+        impl<'a, F : Num + Neg<Output=F>, Domain : Clone> Neg for $type {
+            type Output = DeltaMeasure<Domain, F>;
+            fn $fn(self) -> Self::Output {
+                let mut tmp = self.clone();
+                tmp.α = tmp.α.$fn();
+                tmp
+            }
+        }
+    }
+}
+
+make_delta_unary!(Neg, neg, DeltaMeasure<Domain, F>);
+make_delta_unary!(Neg, neg, &'a DeltaMeasure<Domain, F>);
+

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