ROL
ROL_HouseholderReflector.hpp
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43
44#ifndef ROL_HOUSEHOLDERREFLECTOR_H
45#define ROL_HOUSEHOLDERREFLECTOR_H
46
48
72namespace ROL {
73
74template <class Real>
76
77 typedef Vector<Real> V;
78
79private:
80
81 const ROL::Ptr<const V> x_;
82 const ROL::Ptr<const V> y_;
83
84 ROL::Ptr<V> u_;
85
86public:
87
88 HouseholderReflector( const ROL::Ptr<const Vector<Real> > &x,
89 const ROL::Ptr<const Vector<Real> > &y) : x_(x), y_(y), u_(x->clone()) {}
90
91
92 HouseholderReflector( const ROL::Ptr<const Vector<Real> > &x,
93 const ROL::Ptr<const Vector<Real> > &y,
94 ROL::Ptr<Vector<Real> > &scratch ) : x_(x), y_(y), u_(scratch) {}
95
96 HouseholderReflector( const ROL::Ptr<const Vector<Real> > &x ) : x_(x), y_(x->basis(0)), u_(x->clone()) {}
97
98 HouseholderReflector( const ROL::Ptr<const Vector<Real> > &x,
99 ROL::Ptr<Vector<Real> > &scratch ) : x_(x), y_(x->basis(0)), u_(scratch) {}
100
101
102
103 void apply( Vector<Real> &Hv, const Vector<Real> &v, Real &tol ) const {
104
105 Real xdoty = x_->dot(*y_);
106 Real xnorm = x_->norm();
107 Real ynorm = y_->norm();
108 Real sgn = xdoty/std::abs(xdoty);
109
110 Real alpha = sgn*xnorm/ynorm;
111
112 u_->set(*x_);
113 u_->axpy(alpha,*y_);
114
115 Real beta = -2.0*u_->dot(v)/u_->dot(*u_);
116
117 Hv.set(v);
118 Hv.axpy(beta,*u_);
119 }
120
121 void applyInverse( Vector<Real> &Hv, const Vector<Real> &v, Real &tol ) const {
122 apply(Hv,v,tol);
123 }
124
125}; // class HouseholderReflector
126
127} // namespace ROL
128
129#endif // ROL_HOUSEHOLDERREFLECTOR_H
Provides the interface to create a Householder reflector operator, that when applied to a vector x,...
HouseholderReflector(const ROL::Ptr< const Vector< Real > > &x)
HouseholderReflector(const ROL::Ptr< const Vector< Real > > &x, const ROL::Ptr< const Vector< Real > > &y, ROL::Ptr< Vector< Real > > &scratch)
void apply(Vector< Real > &Hv, const Vector< Real > &v, Real &tol) const
Apply linear operator.
HouseholderReflector(const ROL::Ptr< const Vector< Real > > &x, ROL::Ptr< Vector< Real > > &scratch)
void applyInverse(Vector< Real > &Hv, const Vector< Real > &v, Real &tol) const
Apply inverse of linear operator.
HouseholderReflector(const ROL::Ptr< const Vector< Real > > &x, const ROL::Ptr< const Vector< Real > > &y)
Provides the interface to apply a linear operator.
Defines the linear algebra or vector space interface.
virtual void set(const Vector &x)
Set where .
virtual void axpy(const Real alpha, const Vector &x)
Compute where .