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1 /*! |
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2 Solver for the point source localisation problem using a sliding |
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3 primal-dual proximal splitting method. |
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4 */ |
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5 |
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6 use numeric_literals::replace_float_literals; |
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7 use serde::{Serialize, Deserialize}; |
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8 //use colored::Colorize; |
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9 //use nalgebra::{DVector, DMatrix}; |
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10 use std::iter::Iterator; |
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11 |
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12 use alg_tools::iterate::AlgIteratorFactory; |
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13 use alg_tools::euclidean::Euclidean; |
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14 use alg_tools::sets::Cube; |
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15 use alg_tools::loc::Loc; |
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16 use alg_tools::mapping::{Mapping, DifferentiableRealMapping, Instance}; |
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17 use alg_tools::norms::Norm; |
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18 use alg_tools::direct_product::Pair; |
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19 use alg_tools::bisection_tree::{ |
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20 BTFN, |
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21 PreBTFN, |
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22 Bounds, |
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23 BTNodeLookup, |
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24 BTNode, |
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25 BTSearch, |
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26 P2Minimise, |
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27 SupportGenerator, |
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28 LocalAnalysis, |
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29 //Bounded, |
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30 }; |
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31 use alg_tools::mapping::RealMapping; |
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32 use alg_tools::nalgebra_support::ToNalgebraRealField; |
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33 use alg_tools::linops::{ |
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34 BoundedLinear, AXPY, GEMV, Adjointable, IdOp, |
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35 }; |
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36 use alg_tools::convex::{Conjugable, Prox}; |
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37 use alg_tools::norms::{L2, Linfinity, PairNorm}; |
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38 |
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39 use crate::types::*; |
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40 use crate::measures::{DiscreteMeasure, Radon, RNDM}; |
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41 use crate::measures::merging::SpikeMerging; |
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42 use crate::forward_model::{ |
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43 ForwardModel, |
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44 AdjointProductPairBoundedBy, |
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45 LipschitzValues, |
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46 }; |
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47 // use crate::transport::TransportLipschitz; |
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48 use crate::seminorms::DiscreteMeasureOp; |
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49 //use crate::tolerance::Tolerance; |
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50 use crate::plot::{ |
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51 SeqPlotter, |
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52 Plotting, |
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53 PlotLookup |
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54 }; |
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55 use crate::fb::*; |
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56 use crate::regularisation::SlidingRegTerm; |
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57 // use crate::dataterm::L2Squared; |
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58 use crate::sliding_fb::{ |
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59 TransportConfig, |
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60 TransportStepLength, |
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61 initial_transport, |
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62 aposteriori_transport, |
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63 }; |
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64 use crate::dataterm::{calculate_residual, calculate_residual2}; |
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65 |
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66 /// Settings for [`pointsource_sliding_pdps_pair`]. |
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67 #[derive(Clone, Copy, Eq, PartialEq, Serialize, Deserialize, Debug)] |
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68 #[serde(default)] |
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69 pub struct SlidingPDPSConfig<F : Float> { |
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70 /// Primal step length scaling. |
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71 pub τ0 : F, |
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72 /// Primal step length scaling. |
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73 pub σp0 : F, |
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74 /// Dual step length scaling. |
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75 pub σd0 : F, |
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76 /// Transport parameters |
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77 pub transport : TransportConfig<F>, |
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78 /// Generic parameters |
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79 pub insertion : FBGenericConfig<F>, |
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80 } |
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81 |
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82 #[replace_float_literals(F::cast_from(literal))] |
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83 impl<F : Float> Default for SlidingPDPSConfig<F> { |
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84 fn default() -> Self { |
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85 let τ0 = 0.99; |
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86 SlidingPDPSConfig { |
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87 τ0, |
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88 σd0 : 0.1, |
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89 σp0 : 0.99, |
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90 transport : Default::default(), |
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91 insertion : Default::default() |
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92 } |
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93 } |
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94 } |
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95 |
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96 type MeasureZ<F, Z, const N : usize> = Pair<RNDM<F, N>, Z>; |
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97 |
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98 /// Iteratively solve the pointsource localisation with an additional variable |
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99 /// using sliding primal-dual proximal splitting |
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100 /// |
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101 /// The parametrisation is as for [`crate::forward_pdps::pointsource_forward_pdps_pair`]. |
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102 #[replace_float_literals(F::cast_from(literal))] |
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103 pub fn pointsource_sliding_pdps_pair< |
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104 'a, F, I, A, GA, 𝒟, BTA, BT𝒟, G𝒟, S, K, Reg, Z, R, Y, /*KOpM, */ KOpZ, H, const N : usize |
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105 >( |
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106 opA : &'a A, |
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107 b : &A::Observable, |
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108 reg : Reg, |
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109 op𝒟 : &'a 𝒟, |
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110 config : &SlidingPDPSConfig<F>, |
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111 iterator : I, |
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112 mut plotter : SeqPlotter<F, N>, |
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113 //opKμ : KOpM, |
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114 opKz : &KOpZ, |
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115 fnR : &R, |
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116 fnH : &H, |
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117 mut z : Z, |
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118 mut y : Y, |
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119 ) -> MeasureZ<F, Z, N> |
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120 where |
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121 F : Float + ToNalgebraRealField, |
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122 I : AlgIteratorFactory<IterInfo<F, N>>, |
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123 for<'b> &'b A::Observable : std::ops::Neg<Output=A::Observable> + Instance<A::Observable>, |
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124 for<'b> A::Preadjoint<'b> : LipschitzValues<FloatType=F>, |
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125 BTFN<F, GA, BTA, N> : DifferentiableRealMapping<F, N>, |
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126 GA : SupportGenerator<F, N, SupportType = S, Id = usize> + Clone, |
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127 A : ForwardModel< |
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128 MeasureZ<F, Z, N>, |
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129 F, |
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130 PairNorm<Radon, L2, L2>, |
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131 PreadjointCodomain = Pair<BTFN<F, GA, BTA, N>, Z>, |
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132 > |
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133 + AdjointProductPairBoundedBy<MeasureZ<F, Z, N>, 𝒟, IdOp<Z>, FloatType=F>, |
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134 BTA : BTSearch<F, N, Data=usize, Agg=Bounds<F>>, |
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135 G𝒟 : SupportGenerator<F, N, SupportType = K, Id = usize> + Clone, |
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136 𝒟 : DiscreteMeasureOp<Loc<F, N>, F, PreCodomain = PreBTFN<F, G𝒟, N>, |
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137 Codomain = BTFN<F, G𝒟, BT𝒟, N>>, |
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138 BT𝒟 : BTSearch<F, N, Data=usize, Agg=Bounds<F>>, |
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139 S: RealMapping<F, N> + LocalAnalysis<F, Bounds<F>, N> |
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140 + DifferentiableRealMapping<F, N>, |
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141 K: RealMapping<F, N> + LocalAnalysis<F, Bounds<F>, N>, |
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142 //+ Differentiable<Loc<F, N>, Derivative=Loc<F,N>>, |
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143 BTNodeLookup: BTNode<F, usize, Bounds<F>, N>, |
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144 Cube<F, N>: P2Minimise<Loc<F, N>, F>, |
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145 PlotLookup : Plotting<N>, |
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146 RNDM<F, N> : SpikeMerging<F>, |
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147 Reg : SlidingRegTerm<F, N>, |
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148 // KOpM : Linear<RNDM<F, N>, Codomain=Y> |
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149 // + GEMV<F, RNDM<F, N>> |
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150 // + Preadjointable< |
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151 // RNDM<F, N>, Y, |
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152 // PreadjointCodomain = BTFN<F, GA, BTA, N>, |
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153 // > |
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154 // + TransportLipschitz<L2Squared, FloatType=F> |
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155 // + AdjointProductBoundedBy<RNDM<F, N>, 𝒟, FloatType=F>, |
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156 // for<'b> KOpM::Preadjoint<'b> : GEMV<F, Y>, |
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157 // Since Z is Hilbert, we may just as well use adjoints for K_z. |
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158 KOpZ : BoundedLinear<Z, L2, L2, F, Codomain=Y> |
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159 + GEMV<F, Z> |
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160 + Adjointable<Z, Y, AdjointCodomain = Z>, |
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161 for<'b> KOpZ::Adjoint<'b> : GEMV<F, Y>, |
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162 Y : AXPY<F> + Euclidean<F, Output=Y> + Clone + ClosedAdd, |
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163 for<'b> &'b Y : Instance<Y>, |
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164 Z : AXPY<F, Owned=Z> + Euclidean<F, Output=Z> + Clone + Norm<F, L2>, |
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165 for<'b> &'b Z : Instance<Z>, |
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166 R : Prox<Z, Codomain=F>, |
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167 H : Conjugable<Y, F, Codomain=F>, |
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168 for<'b> H::Conjugate<'b> : Prox<Y>, |
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169 { |
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170 |
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171 // Check parameters |
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172 assert!(config.τ0 > 0.0 && |
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173 config.τ0 < 1.0 && |
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174 config.σp0 > 0.0 && |
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175 config.σp0 < 1.0 && |
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176 config.σd0 > 0.0 && |
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177 config.σp0 * config.σd0 <= 1.0, |
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178 "Invalid step length parameters"); |
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179 config.transport.check(); |
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180 |
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181 // Initialise iterates |
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182 let mut μ = DiscreteMeasure::new(); |
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183 let mut γ1 = DiscreteMeasure::new(); |
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184 let mut residual = calculate_residual(Pair(&μ, &z), opA, b); |
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185 let zero_z = z.similar_origin(); |
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186 |
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187 // Set up parameters |
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188 let op𝒟norm = op𝒟.opnorm_bound(Radon, Linfinity); |
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189 // TODO: maybe this PairNorm doesn't make sense here? |
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190 let opAnorm = opA.opnorm_bound(PairNorm(Radon, L2, L2), L2); |
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191 let bigθ = 0.0; //opKμ.transport_lipschitz_factor(L2Squared); |
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192 let bigM = 0.0; //opKμ.adjoint_product_bound(&op𝒟).unwrap().sqrt(); |
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193 let nKz = opKz.opnorm_bound(L2, L2); |
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194 let ℓ = 0.0; |
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195 let opIdZ = IdOp::new(); |
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196 let (l, l_z) = opA.adjoint_product_pair_bound(&op𝒟, &opIdZ).unwrap(); |
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197 // We need to satisfy |
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198 // |
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199 // τσ_dM(1-σ_p L_z)/(1 - τ L) + [σ_p L_z + σ_pσ_d‖K_z‖^2] < 1 |
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200 // ^^^^^^^^^^^^^^^^^^^^^^^^^ |
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201 // with 1 > σ_p L_z and 1 > τ L. |
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202 // |
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203 // To do so, we first solve σ_p and σ_d from standard PDPS step length condition |
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204 // ^^^^^ < 1. then we solve τ from the rest. |
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205 let σ_d = config.σd0 / nKz; |
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206 let σ_p = config.σp0 / (l_z + config.σd0 * nKz); |
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207 // Observe that = 1 - ^^^^^^^^^^^^^^^^^^^^^ = 1 - σ_{p,0} |
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208 // We get the condition τσ_d M (1-σ_p L_z) < (1-σ_{p,0})*(1-τ L) |
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209 // ⟺ τ [ σ_d M (1-σ_p L_z) + (1-σ_{p,0}) L ] < (1-σ_{p,0}) |
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210 let φ = 1.0 - config.σp0; |
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211 let a = 1.0 - σ_p * l_z; |
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212 let τ = config.τ0 * φ / ( σ_d * bigM * a + φ * l ); |
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213 let ψ = 1.0 - τ * l; |
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214 let β = σ_p * config.σd0 * nKz / a; // σ_p * σ_d * (nKz * nK_z) / a; |
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215 assert!(β < 1.0); |
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216 // Now we need κ‖K_μ(π_♯^1 - π_♯^0)γ‖^2 ≤ (1/θ - τ[ℓ_v + ℓ]) ∫ c_2 dγ for κ defined as: |
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217 let κ = σ_d * ψ / ((1.0 - β) * ψ - τ * σ_d * bigM); |
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218 // The factor two in the manuscript disappears due to the definition of 𝚹 being |
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219 // for ‖x-y‖₂² instead of c_2(x, y)=‖x-y‖₂²/2. |
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220 let calculate_θ = |ℓ_v, max_transport| { |
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221 config.transport.θ0 / (τ*(ℓ + ℓ_v) + κ * bigθ * max_transport) |
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222 }; |
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223 let mut θ_or_adaptive = match opA.preadjoint().value_diff_unit_lipschitz_factor() { |
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224 // We only estimate w (the uniform Lipschitz for of v), if we also estimate ℓ_v |
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225 // (the uniform Lipschitz factor of ∇v). |
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226 // We assume that the residual is decreasing. |
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227 Some(ℓ_v0) => TransportStepLength::AdaptiveMax{ |
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228 l: ℓ_v0 * b.norm2(), |
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229 max_transport : 0.0, |
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230 g : calculate_θ |
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231 }, |
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232 None => TransportStepLength::FullyAdaptive{ |
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233 l : 0.0, |
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234 max_transport : 0.0, |
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235 g : calculate_θ |
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236 }, |
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237 }; |
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238 // Acceleration is not currently supported |
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239 // let γ = dataterm.factor_of_strong_convexity(); |
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240 let ω = 1.0; |
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241 |
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242 // We multiply tolerance by τ for FB since our subproblems depending on tolerances are scaled |
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243 // by τ compared to the conditional gradient approach. |
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244 let tolerance = config.insertion.tolerance * τ * reg.tolerance_scaling(); |
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245 let mut ε = tolerance.initial(); |
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246 |
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247 let starH = fnH.conjugate(); |
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248 |
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249 // Statistics |
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250 let full_stats = |residual : &A::Observable, μ : &RNDM<F, N>, z : &Z, ε, stats| IterInfo { |
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251 value : residual.norm2_squared_div2() + fnR.apply(z) |
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252 + reg.apply(μ) + fnH.apply(/* opKμ.apply(μ) + */ opKz.apply(z)), |
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253 n_spikes : μ.len(), |
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254 ε, |
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255 // postprocessing: config.insertion.postprocessing.then(|| μ.clone()), |
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256 .. stats |
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257 }; |
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258 let mut stats = IterInfo::new(); |
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259 |
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260 // Run the algorithm |
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261 for state in iterator.iter_init(|| full_stats(&residual, &μ, &z, ε, stats.clone())) { |
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262 // Calculate initial transport |
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263 let Pair(v, _) = opA.preadjoint().apply(&residual); |
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264 //opKμ.preadjoint().apply_add(&mut v, y); |
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265 let z_base = z.clone(); |
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266 // We want to proceed as in Example 4.12 but with v and v̆ as in §5. |
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267 // With A(ν, z) = A_μ ν + A_z z, following Example 5.1, we have |
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268 // P_ℳ[F'(ν, z) + Ξ(ν, z, y)]= A_ν^*[A_ν ν + A_z z] + K_μ ν = A_ν^*A(ν, z) + K_μ ν, |
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269 // where A_ν^* becomes a multiplier. |
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270 // This is much easier with K_μ = 0, which is the only reason why are enforcing it. |
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271 // TODO: Write a version of initial_transport that can deal with K_μ ≠ 0. |
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272 |
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273 let (μ_base_masses, mut μ_base_minus_γ0) = initial_transport( |
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274 &mut γ1, &mut μ, |ν| opA.apply(Pair(ν, &z)), |
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275 ε, τ, &mut θ_or_adaptive, opAnorm, |
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276 v, &config.transport, |
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277 ); |
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278 |
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279 // Solve finite-dimensional subproblem several times until the dual variable for the |
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280 // regularisation term conforms to the assumptions made for the transport above. |
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281 let (d, _within_tolerances, Pair(τv̆, τz̆)) = 'adapt_transport: loop { |
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282 // Calculate τv̆ = τA_*(A[μ_transported + μ_transported_base]-b) |
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283 let residual_μ̆ = calculate_residual2(Pair(&γ1, &z), |
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284 Pair(&μ_base_minus_γ0, &zero_z), |
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285 opA, b); |
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286 let Pair(τv̆, τz) = opA.preadjoint().apply(residual_μ̆ * τ); |
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287 // opKμ.preadjoint().gemv(&mut τv̆, τ, y, 1.0); |
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288 |
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289 // Construct μ^{k+1} by solving finite-dimensional subproblems and insert new spikes. |
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290 let (d, within_tolerances) = insert_and_reweigh( |
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291 &mut μ, &τv̆, &γ1, Some(&μ_base_minus_γ0), |
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292 op𝒟, op𝒟norm, |
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293 τ, ε, &config.insertion, |
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294 ®, &state, &mut stats, |
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295 ); |
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296 |
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297 // A posteriori transport adaptation. |
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298 // TODO: this does not properly treat v^{k+1} - v̆^k that depends on z^{k+1}! |
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299 if aposteriori_transport( |
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300 &mut γ1, &mut μ, &mut μ_base_minus_γ0, &μ_base_masses, |
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301 ε, &config.transport |
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302 ) { |
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303 break 'adapt_transport (d, within_tolerances, Pair(τv̆, τz)) |
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304 } |
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305 }; |
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306 |
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307 stats.untransported_fraction = Some({ |
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308 assert_eq!(μ_base_masses.len(), γ1.len()); |
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309 let (a, b) = stats.untransported_fraction.unwrap_or((0.0, 0.0)); |
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310 let source = μ_base_masses.iter().map(|v| v.abs()).sum(); |
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311 (a + μ_base_minus_γ0.norm(Radon), b + source) |
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312 }); |
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313 stats.transport_error = Some({ |
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314 assert_eq!(μ_base_masses.len(), γ1.len()); |
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315 let (a, b) = stats.transport_error.unwrap_or((0.0, 0.0)); |
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316 (a + μ.dist_matching(&γ1), b + γ1.norm(Radon)) |
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317 }); |
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318 |
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319 // // Merge spikes. |
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320 // // This expects the prune below to prune γ. |
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321 // // TODO: This may not work correctly in all cases. |
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322 // let ins = &config.insertion; |
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323 // if ins.merge_now(&state) { |
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324 // if let SpikeMergingMethod::None = ins.merging { |
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325 // } else { |
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326 // stats.merged += μ.merge_spikes(ins.merging, |μ_candidate| { |
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327 // let ν = μ_candidate.sub_matching(&γ1)-&μ_base_minus_γ0; |
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328 // let mut d = &τv̆ + op𝒟.preapply(ν); |
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329 // reg.verify_merge_candidate(&mut d, μ_candidate, τ, ε, ins) |
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330 // }); |
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331 // } |
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332 // } |
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333 |
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334 // Prune spikes with zero weight. To maintain correct ordering between μ and γ1, also the |
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335 // latter needs to be pruned when μ is. |
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336 // TODO: This could do with a two-vector Vec::retain to avoid copies. |
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337 let μ_new = DiscreteMeasure::from_iter(μ.iter_spikes().filter(|δ| δ.α != F::ZERO).cloned()); |
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338 if μ_new.len() != μ.len() { |
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339 let mut μ_iter = μ.iter_spikes(); |
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340 γ1.prune_by(|_| μ_iter.next().unwrap().α != F::ZERO); |
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341 stats.pruned += μ.len() - μ_new.len(); |
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342 μ = μ_new; |
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343 } |
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344 |
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345 // Do z variable primal update |
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346 z.axpy(-σ_p/τ, τz̆, 1.0); // TODO: simplify nasty factors |
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347 opKz.adjoint().gemv(&mut z, -σ_p, &y, 1.0); |
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348 z = fnR.prox(σ_p, z); |
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349 // Do dual update |
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350 // opKμ.gemv(&mut y, σ_d*(1.0 + ω), &μ, 1.0); // y = y + σ_d K[(1+ω)(μ,z)^{k+1}] |
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351 opKz.gemv(&mut y, σ_d*(1.0 + ω), &z, 1.0); |
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352 // opKμ.gemv(&mut y, -σ_d*ω, μ_base, 1.0);// y = y + σ_d K[(1+ω)(μ,z)^{k+1} - ω (μ,z)^k]-b |
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353 opKz.gemv(&mut y, -σ_d*ω, z_base, 1.0);// y = y + σ_d K[(1+ω)(μ,z)^{k+1} - ω (μ,z)^k]-b |
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354 y = starH.prox(σ_d, y); |
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355 |
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356 // Update residual |
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357 residual = calculate_residual(Pair(&μ, &z), opA, b); |
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358 |
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359 // Update step length parameters |
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360 // let ω = pdpsconfig.acceleration.accelerate(&mut τ, &mut σ, γ); |
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361 |
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362 // Give statistics if requested |
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363 let iter = state.iteration(); |
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364 stats.this_iters += 1; |
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365 |
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366 state.if_verbose(|| { |
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367 plotter.plot_spikes(iter, Some(&d), Some(&τv̆), &μ); |
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368 full_stats(&residual, &μ, &z, ε, std::mem::replace(&mut stats, IterInfo::new())) |
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369 }); |
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370 |
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371 // Update main tolerance for next iteration |
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372 ε = tolerance.update(ε, iter); |
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373 } |
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374 |
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375 let fit = |μ̃ : &RNDM<F, N>| { |
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376 (opA.apply(Pair(μ̃, &z))-b).norm2_squared_div2() |
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377 //+ fnR.apply(z) + reg.apply(μ) |
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378 + fnH.apply(/* opKμ.apply(&μ̃) + */ opKz.apply(&z)) |
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379 }; |
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380 |
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381 μ.merge_spikes_fitness(config.insertion.merging, fit, |&v| v); |
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382 μ.prune(); |
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383 Pair(μ, z) |
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384 } |