ROL
ROL_CoherentEntropicRisk.hpp
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1 // @HEADER
2 // *****************************************************************************
3 // Rapid Optimization Library (ROL) Package
4 //
5 // Copyright 2014 NTESS and the ROL contributors.
6 // SPDX-License-Identifier: BSD-3-Clause
7 // *****************************************************************************
8 // @HEADER
9 
10 #ifndef ROL_COHERENTEXPUTILITY_HPP
11 #define ROL_COHERENTEXPUTILITY_HPP
12 
14 
30 namespace ROL {
31 
32 template<class Real>
34 private:
35  Real dval1_;
36  Real dval2_;
37  Real dval3_;
38 
44 
46 
51 
52 public:
54  dval1_(0), dval2_(0), dval3_(0) {}
55 
56  void initialize(const Vector<Real> &x) {
58  Real zero(0);
59  dval1_ = zero; dval2_ = zero; dval3_ = zero;
60  }
61 
63  const Vector<Real> &x,
64  const std::vector<Real> &xstat,
65  Real &tol) {
66  Real val = computeValue(obj,x,tol);
67  val_ += weight_ * std::exp(val/xstat[0]);
68  }
69 
70  Real getValue(const Vector<Real> &x,
71  const std::vector<Real> &xstat,
72  SampleGenerator<Real> &sampler) {
73  Real ev(0);
74  sampler.sumAll(&val_,&ev,1);
75  return xstat[0]*std::log(ev);
76  }
77 
79  const Vector<Real> &x,
80  const std::vector<Real> &xstat,
81  Real &tol) {
82  Real val = computeValue(obj,x,tol);
83  Real ev = std::exp(val/xstat[0]);
84  val_ += weight_ * ev;
85  gv_ += weight_ * ev * val;
86  computeGradient(*dualVector_,obj,x,tol);
87  g_->axpy(weight_*ev,*dualVector_);
88  }
89 
91  std::vector<Real> &gstat,
92  const Vector<Real> &x,
93  const std::vector<Real> &xstat,
94  SampleGenerator<Real> &sampler) {
95  const Real one(1);
96  // Perform sum over batches
97  std::vector<Real> myval(2,0), val(2,0);
98  myval[0] = val_;
99  myval[1] = gv_;
100  sampler.sumAll(&myval[0],&val[0],2);
101 
102  sampler.sumAll(*g_,g);
103  g.scale(one/val[0]);
104  gstat[0] = std::log(val[0]) - val[1]/(val[0]*xstat[0]);
105  }
106 
108  const Vector<Real> &v,
109  const std::vector<Real> &vstat,
110  const Vector<Real> &x,
111  const std::vector<Real> &xstat,
112  Real &tol) {
113  Real val = computeValue(obj,x,tol);
114  Real ev = std::exp(val/xstat[0]);
115  val_ += weight_ * ev;
116 
117  Real gv = computeGradVec(*dualVector_,obj,v,x,tol);
118  gv_ += weight_ * ev * gv;
119  g_->axpy(weight_*ev,*dualVector_);
120  hv_->axpy(weight_*ev*(gv-val*vstat[0]/xstat[0])/xstat[0],*dualVector_);
121 
122  dval1_ += weight_ * ev * val;
123  dval2_ += weight_ * ev * val * val;
124  dval3_ += weight_ * ev * val * gv;
125 
126  computeHessVec(*dualVector_,obj,v,x,tol);
127  hv_->axpy(weight_*ev,*dualVector_);
128  }
129 
131  std::vector<Real> &hvstat,
132  const Vector<Real> &v,
133  const std::vector<Real> &vstat,
134  const Vector<Real> &x,
135  const std::vector<Real> &xstat,
136  SampleGenerator<Real> &sampler) {
137  const Real one(1);
138  std::vector<Real> myval(5,0), val(5,0);
139  myval[0] = val_;
140  myval[1] = gv_;
141  myval[2] = dval1_;
142  myval[3] = dval2_;
143  myval[4] = dval3_;
144  sampler.sumAll(&myval[0],&val[0],5);
145 
146  Real xs2 = xstat[0]*xstat[0];
147  Real xs3 = xs2*xstat[0];
148  Real v02 = val[0]*val[0];
149  Real h11 = (val[3]*val[0] - val[2]*val[2])/(v02*xs3) * vstat[0];
150  Real h12 = (val[1]*val[2] - val[4]*val[0])/(v02*xs2);
151  hvstat[0] = h11+h12;
152  sampler.sumAll(*hv_,hv);
153  hv.scale(one/val[0]);
154 
155  dualVector_->zero();
156  sampler.sumAll(*g_,*dualVector_);
157  hv.axpy((vstat[0]*val[2]/xs2-val[1]/xstat[0])/v02,*dualVector_);
158  }
159 };
160 
161 }
162 
163 #endif
Provides the interface to evaluate objective functions.
void computeHessVec(Vector< Real > &hv, Objective< Real > &obj, const Vector< Real > &v, const Vector< Real > &x, Real &tol)
virtual void scale(const Real alpha)=0
Compute where .
Ptr< Vector< Real > > g_
Real computeValue(Objective< Real > &obj, const Vector< Real > &x, Real &tol)
virtual void axpy(const Real alpha, const Vector &x)
Compute where .
Definition: ROL_Vector.hpp:119
Ptr< Vector< Real > > hv_
Ptr< Vector< Real > > dualVector_
Defines the linear algebra or vector space interface.
Definition: ROL_Vector.hpp:46
void sumAll(Real *input, Real *output, int dim) const
Real getValue(const Vector< Real > &x, const std::vector< Real > &xstat, SampleGenerator< Real > &sampler)
Return risk measure value.
Objective_SerialSimOpt(const Ptr< Obj > &obj, const V &ui) z0_ zero()
void updateHessVec(Objective< Real > &obj, const Vector< Real > &v, const std::vector< Real > &vstat, const Vector< Real > &x, const std::vector< Real > &xstat, Real &tol)
Update internal risk measure storage for Hessian-time-a-vector computation.
Provides the interface for the coherent entropic risk measure.
void getHessVec(Vector< Real > &hv, std::vector< Real > &hvstat, const Vector< Real > &v, const std::vector< Real > &vstat, const Vector< Real > &x, const std::vector< Real > &xstat, SampleGenerator< Real > &sampler)
Return risk measure Hessian-times-a-vector.
void updateValue(Objective< Real > &obj, const Vector< Real > &x, const std::vector< Real > &xstat, Real &tol)
Update internal storage for value computation.
void computeGradient(Vector< Real > &g, Objective< Real > &obj, const Vector< Real > &x, Real &tol)
Real computeGradVec(Vector< Real > &g, Objective< Real > &obj, const Vector< Real > &v, const Vector< Real > &x, Real &tol)
Provides the interface to implement any functional that maps a random variable to a (extended) real n...
void initialize(const Vector< Real > &x)
Initialize temporary variables.
void updateGradient(Objective< Real > &obj, const Vector< Real > &x, const std::vector< Real > &xstat, Real &tol)
Update internal risk measure storage for gradient computation.
void getGradient(Vector< Real > &g, std::vector< Real > &gstat, const Vector< Real > &x, const std::vector< Real > &xstat, SampleGenerator< Real > &sampler)
Return risk measure (sub)gradient.
virtual void initialize(const Vector< Real > &x)
Initialize temporary variables.