1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

//! Feature Extraction Module

use std::marker::PhantomData;
use std::fmt::Debug;

use num::Float;
use num::cast::NumCast;

use environment::Space;

use util::{Feature, Metric};

/// Identity Feature
///
/// Attempts to convert (state, action) pair into a Vec and returns the ith component
#[derive(Debug, Clone)]
pub struct IFeature<F: Float + Debug + 'static, T: Debug + Into<F>> {
	index: usize,
	phant1: PhantomData<T>,
	phant2: PhantomData<F>,
}

impl<F: Float + Debug + 'static, S: Space, T> Feature<S, F> for IFeature<F, T>
	where T: Into<F> + Debug + Clone + 'static,
		  S::Element: Into<Vec<T>> {
	fn extract(&self, state: &S::Element) -> F {
		state.clone().into()[self.index].clone().into()
	}
	fn box_clone(&self) -> Box<Feature<S, F>> {
		Box::new(self.clone())
	}
}

impl<F: Float + Debug + 'static, T: Debug + Into<F>> IFeature<F, T> {
	/// Creates a new Identity Feature
	pub fn new(index: usize) -> IFeature<F, T> {
		IFeature {index: index, phant1: PhantomData, phant2: PhantomData}
	}
}

/// Radial Basis (Function) Feature
///
/// Computes feature exp(-||s-s'||^2/(2u^2))
/// Represents a gaussian centered at s' with standard deviation u
#[derive(Debug, Clone)]
pub struct RBFeature<F:Float + Debug + 'static, S: Space> {
	center: S::Element,
	variation: F,
}

impl<F: Float + Debug + 'static, S: Space + Clone + 'static> Feature<S, F> for RBFeature<F, S> 
	where S::Element: Metric {
	fn extract(&self, state: &S::Element) -> F {
		let two = F::one() + F::one();
		let dist2: F = NumCast::from(Metric::dist2(state, &self.center)).unwrap();
		(-dist2/(two*self.variation)).exp()
	}
	fn box_clone(&self) -> Box<Feature<S, F>> {
		Box::new((*self).clone())
	}
}

impl<F: Float + Debug + 'static, S: Space> RBFeature<F, S> {
	/// Creates a new RBFeature with given center and standard deviation
	pub fn new(center: S::Element, deviation: F) -> RBFeature<F, S> {
		RBFeature {
			center: center,
			variation: deviation*deviation
		}
	}
}

/// Binary Ball Feature
///
/// 1 iff the state is close enough to the center
#[derive(Debug, Clone)]
pub struct BBFeature<F: Float + Debug + 'static, S: Space> {
	center: S::Element,
	radius: F,
}

impl<F: Float + Debug + 'static, S: Space + Clone + 'static> Feature<S, F> for BBFeature<F, S> 
	where S::Element: Metric {
	fn extract(&self, state: &S::Element) -> F {
		let dist2: F = NumCast::from(Metric::dist2(state, &self.center)).unwrap();
		if dist2 <= self.radius*self.radius {F::one()} else {F::zero()}
	}
	fn box_clone(&self) -> Box<Feature<S, F>> {
		Box::new(self.clone())
	}
}

impl<F: Float + Debug + 'static, S: Space> BBFeature<F, S> {
	/// Creates a new BBFeature
	pub fn new(center: S::Element, radius: F) -> BBFeature<F, S> {
		BBFeature {
			center: center,
			radius: radius
		}
	}
}

/// Binary Slice Feature
///
/// 1 iff the value in the specified dimension is in the given range
#[derive(Debug, Clone)]
pub struct BSFeature<F: Float + Debug + 'static, T: Debug + Into<F>> {
	min: F,
	max: F,
	dim: usize,
	phantom: PhantomData<T>,
}

impl<F: Float + Debug + 'static + 'static, S: Space, T> Feature<S, F> for BSFeature<F, T> 
	where T: Into<F> + Debug + Clone + 'static,
		  S::Element: Into<Vec<T>> {
	fn extract(&self, state: &S::Element) -> F {
		let val = state.clone().into()[self.dim].clone().into();
		if self.min <= val && val <= self.max {F::one()} else {F::zero()}
	}
	fn box_clone(&self) -> Box<Feature<S, F>> {
		Box::new(self.clone())
	}
}

impl<F: Float + Debug + 'static, T: Debug + Into<F>> BSFeature<F, T> {
	/// Creates a new BSFeature
	pub fn new(min: F, max: F, dim: usize) -> BSFeature<F, T> {
		BSFeature {
			min: min,
			max: max,
			dim: dim,
			phantom: PhantomData
		}
	}
}