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QMR implemented, preserve even if not used much

This commit is contained in:
Peter Boyle 2019-12-09 02:59:13 -05:00
parent 3d2fe80780
commit 58a31f0763

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/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/algorithmsf/iterative/QuasiMinimalResidual.h
Copyright (C) 2019
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution
directory
*************************************************************************************/
/* END LEGAL */
#pragma once
NAMESPACE_BEGIN(Grid);
template<class Field>
RealD innerG5ProductReal(Field &l, Field &r)
{
Gamma G5(Gamma::Algebra::Gamma5);
Field tmp(l.Grid());
// tmp = G5*r;
G5R5(tmp,r);
ComplexD ip =innerProduct(l,tmp);
std::cout << "innerProductRealG5R5 "<<ip<<std::endl;
return ip.real();
}
template<class Field>
class QuasiMinimalResidual : public OperatorFunction<Field> {
public:
using OperatorFunction<Field>::operator();
bool ErrorOnNoConverge;
RealD Tolerance;
Integer MaxIterations;
Integer IterationCount;
QuasiMinimalResidual(RealD tol,
Integer maxit,
bool err_on_no_conv = true)
: Tolerance(tol)
, MaxIterations(maxit)
, ErrorOnNoConverge(err_on_no_conv)
{};
#if 1
void operator()(LinearOperatorBase<Field> &LinOp, const Field &b, Field &x)
{
RealD resid;
IterationCount=0;
RealD rho, rho_1, xi, gamma, gamma_1, theta, theta_1;
RealD eta, delta, ep, beta;
GridBase *Grid = b.Grid();
Field r(Grid), d(Grid), s(Grid);
Field v(Grid), w(Grid), y(Grid), z(Grid);
Field v_tld(Grid), w_tld(Grid), y_tld(Grid), z_tld(Grid);
Field p(Grid), q(Grid), p_tld(Grid);
Real normb = norm2(b);
LinOp.Op(x,r); r = b - r;
assert(normb> 0.0);
resid = norm2(r)/normb;
if (resid <= Tolerance) {
return;
}
v_tld = r;
y = v_tld;
rho = norm2(y);
// Take Gamma5 conjugate
// Gamma G5(Gamma::Algebra::Gamma5);
// G5R5(w_tld,r);
// w_tld = G5* v_tld;
w_tld=v_tld;
z = w_tld;
xi = norm2(z);
gamma = 1.0;
eta = -1.0;
theta = 0.0;
for (int i = 1; i <= MaxIterations; i++) {
// Breakdown tests
assert( rho != 0.0);
assert( xi != 0.0);
v = (1. / rho) * v_tld;
y = (1. / rho) * y;
w = (1. / xi) * w_tld;
z = (1. / xi) * z;
ComplexD Zdelta = innerProduct(z, y); // Complex?
std::cout << "Zdelta "<<Zdelta<<std::endl;
delta = Zdelta.real();
y_tld = y;
z_tld = z;
if (i > 1) {
p = y_tld - (xi * delta / ep) * p;
q = z_tld - (rho * delta / ep) * q;
} else {
p = y_tld;
q = z_tld;
}
LinOp.Op(p,p_tld); // p_tld = A * p;
ComplexD Zep = innerProduct(q, p_tld);
ep=Zep.real();
std::cout << "Zep "<<Zep <<std::endl;
// Complex Audit
assert(abs(ep)>0);
beta = ep / delta;
assert(abs(beta)>0);
v_tld = p_tld - beta * v;
y = v_tld;
rho_1 = rho;
rho = norm2(y);
LinOp.AdjOp(q,w_tld);
w_tld = w_tld - beta * w;
z = w_tld;
xi = norm2(z);
gamma_1 = gamma;
theta_1 = theta;
theta = rho / (gamma_1 * beta);
gamma = 1.0 / sqrt(1.0 + theta * theta);
std::cout << "theta "<<theta<<std::endl;
std::cout << "gamma "<<gamma<<std::endl;
assert(abs(gamma)> 0.0);
eta = -eta * rho_1 * gamma* gamma / (beta * gamma_1 * gamma_1);
if (i > 1) {
d = eta * p + (theta_1 * theta_1 * gamma * gamma) * d;
s = eta * p_tld + (theta_1 * theta_1 * gamma * gamma) * s;
} else {
d = eta * p;
s = eta * p_tld;
}
x =x+d; // update approximation vector
r =r-s; // compute residual
if ((resid = norm2(r) / normb) <= Tolerance) {
return;
}
std::cout << "Iteration "<<i<<" resid " << resid<<std::endl;
}
assert(0);
return; // no convergence
}
#else
// QMRg5 SMP thesis
void operator()(LinearOperatorBase<Field> &LinOp, const Field &b, Field &x)
{
// Real scalars
GridBase *grid = b.Grid();
Field r(grid);
Field p_m(grid), p_m_minus_1(grid), p_m_minus_2(grid);
Field v_m(grid), v_m_minus_1(grid), v_m_plus_1(grid);
Field tmp(grid);
RealD w;
RealD z1, z2;
RealD delta_m, delta_m_minus_1;
RealD c_m_plus_1, c_m, c_m_minus_1;
RealD s_m_plus_1, s_m, s_m_minus_1;
RealD alpha, beta, gamma, epsilon;
RealD mu, nu, rho, theta, xi, chi;
RealD mod2r, mod2b;
RealD tau2, target2;
mod2b=norm2(b);
/////////////////////////
// Initial residual
/////////////////////////
LinOp.Op(x,tmp);
r = b - tmp;
/////////////////////////
// \mu = \rho = |r_0|
/////////////////////////
mod2r = norm2(r);
rho = sqrt( mod2r);
mu=rho;
std::cout << "QuasiMinimalResidual rho "<< rho<<std::endl;
/////////////////////////
// Zero negative history
/////////////////////////
v_m_plus_1 = Zero();
v_m_minus_1 = Zero();
p_m_minus_1 = Zero();
p_m_minus_2 = Zero();
// v0
v_m = (1.0/rho)*r;
/////////////////////////
// Initial coeffs
/////////////////////////
delta_m_minus_1 = 1.0;
c_m_minus_1 = 1.0;
c_m = 1.0;
s_m_minus_1 = 0.0;
s_m = 0.0;
/////////////////////////
// Set up convergence check
/////////////////////////
tau2 = mod2r;
target2 = mod2b * Tolerance*Tolerance;
for(int iter = 0 ; iter < MaxIterations; iter++){
/////////////////////////
// \delta_m = (v_m, \gamma_5 v_m)
/////////////////////////
delta_m = innerG5ProductReal(v_m,v_m);
std::cout << "QuasiMinimalResidual delta_m "<< delta_m<<std::endl;
/////////////////////////
// tmp = A v_m
/////////////////////////
LinOp.Op(v_m,tmp);
/////////////////////////
// \alpha = (v_m, \gamma_5 temp) / \delta_m
/////////////////////////
alpha = innerG5ProductReal(v_m,tmp);
alpha = alpha/delta_m ;
std::cout << "QuasiMinimalResidual alpha "<< alpha<<std::endl;
/////////////////////////
// \beta = \rho \delta_m / \delta_{m-1}
/////////////////////////
beta = rho * delta_m / delta_m_minus_1;
std::cout << "QuasiMinimalResidual beta "<< beta<<std::endl;
/////////////////////////
// \tilde{v}_{m+1} = temp - \alpha v_m - \beta v_{m-1}
/////////////////////////
v_m_plus_1 = tmp - alpha*v_m - beta*v_m_minus_1;
///////////////////////////////
// \rho = || \tilde{v}_{m+1} ||
///////////////////////////////
rho = sqrt( norm2(v_m_plus_1) );
std::cout << "QuasiMinimalResidual rho "<< rho<<std::endl;
///////////////////////////////
// v_{m+1} = \tilde{v}_{m+1}
///////////////////////////////
v_m_plus_1 = (1.0 / rho) * v_m_plus_1;
////////////////////////////////
// QMR recurrence coefficients.
////////////////////////////////
theta = s_m_minus_1 * beta;
gamma = c_m_minus_1 * beta;
epsilon = c_m * gamma + s_m * alpha;
xi = -s_m * gamma + c_m * alpha;
nu = sqrt( xi*xi + rho*rho );
c_m_plus_1 = fabs(xi) / nu;
if ( xi == 0.0 ) {
s_m_plus_1 = 1.0;
} else {
s_m_plus_1 = c_m_plus_1 * rho / xi;
}
chi = c_m_plus_1 * xi + s_m_plus_1 * rho;
std::cout << "QuasiMinimalResidual coeffs "<< theta <<" "<<gamma<<" "<< epsilon<<" "<< xi<<" "<< nu<<std::endl;
std::cout << "QuasiMinimalResidual coeffs "<< chi <<std::endl;
////////////////////////////////
//p_m=(v_m - \epsilon p_{m-1} - \theta p_{m-2}) / \chi
////////////////////////////////
p_m = (1.0/chi) * v_m - (epsilon/chi) * p_m_minus_1 - (theta/chi) * p_m_minus_2;
////////////////////////////////////////////////////////////////
// \psi = \psi + c_{m+1} \mu p_m
////////////////////////////////////////////////////////////////
x = x + ( c_m_plus_1 * mu ) * p_m;
////////////////////////////////////////
//
////////////////////////////////////////
mu = -s_m_plus_1 * mu;
delta_m_minus_1 = delta_m;
c_m_minus_1 = c_m;
c_m = c_m_plus_1;
s_m_minus_1 = s_m;
s_m = s_m_plus_1;
////////////////////////////////////
// Could use pointer swizzle games.
////////////////////////////////////
v_m_minus_1 = v_m;
v_m = v_m_plus_1;
p_m_minus_2 = p_m_minus_1;
p_m_minus_1 = p_m;
/////////////////////////////////////
// Convergence checks
/////////////////////////////////////
z1 = RealD(iter+1.0);
z2 = z1 + 1.0;
tau2 = tau2 *( z2 / z1 ) * s_m * s_m;
std::cout << " QuasiMinimumResidual iteration "<< iter<<std::endl;
std::cout << " QuasiMinimumResidual tau bound "<< tau2<<std::endl;
// Compute true residual
mod2r = tau2;
if ( 1 || (tau2 < (100.0 * target2)) ) {
LinOp.Op(x,tmp);
r = b - tmp;
mod2r = norm2(r);
std::cout << " QuasiMinimumResidual true residual is "<< mod2r<<std::endl;
}
if ( mod2r < target2 ) {
std::cout << " QuasiMinimumResidual has converged"<<std::endl;
return;
}
}
}
#endif
};
NAMESPACE_END(Grid);