221 lines
6.4 KiB
C++
221 lines
6.4 KiB
C++
/*
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* Copyright © 2005 Ondra Kamenik
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* Copyright © 2019 Dynare Team
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*
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* This file is part of Dynare.
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*
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* Dynare is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Dynare is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Dynare. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "smolyak.hh"
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#include "symmetry.hh"
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#include <iostream>
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#include <iomanip>
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/* This constructs a beginning of ‘isum’ summand in ‘smolq’. We must be careful
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here, since ‘isum’ can be past-the-end, so no reference to vectors in
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‘smolq’ by ‘isum’ must be done in this case. */
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smolpit::smolpit(const SmolyakQuadrature &q, unsigned int isum)
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: smolq(q), isummand(isum),
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jseq(q.dimen(), 0),
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sig{q.dimen()},
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p{q.dimen()}
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{
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if (isummand < q.numSummands())
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setPointAndWeight();
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}
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bool
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smolpit::operator==(const smolpit &spit) const
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{
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return &smolq == &spit.smolq && isummand == spit.isummand && jseq == spit.jseq;
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}
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/* We first try to increase index within the current summand. If we are at
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maximum, we go to a subsequent summand. Note that in this case all indices
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in ‘jseq’ will be zero, so no change is needed. */
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smolpit &
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smolpit::operator++()
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{
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const IntSequence &levpts = smolq.levpoints[isummand];
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int i = smolq.dimen()-1;
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jseq[i]++;
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while (i >= 0 && jseq[i] == levpts[i])
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{
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jseq[i] = 0;
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i--;
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if (i >= 0)
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jseq[i]++;
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}
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sig.signalAfter(std::max(i, 0));
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if (i < 0)
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isummand++;
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if (isummand < smolq.numSummands())
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setPointAndWeight();
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return *this;
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}
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/* Here we set the point coordinates according to ‘jseq’ and
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‘isummand’. Also the weight is set here. */
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void
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smolpit::setPointAndWeight()
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{
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// todo: raise if isummand ≥ smolq.numSummands()
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int l = smolq.level;
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int d = smolq.dimen();
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int sumk = (smolq.levels[isummand]).sum();
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int m1exp = l + d - sumk - 1;
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w = (2*(m1exp/2) == m1exp) ? 1.0 : -1.0;
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w *= PascalTriangle::noverk(d-1, sumk-l);
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for (int i = 0; i < d; i++)
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{
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int ki = (smolq.levels[isummand])[i];
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p[i] = (smolq.uquad).point(ki, jseq[i]);
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w *= (smolq.uquad).weight(ki, jseq[i]);
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}
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}
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/* Debug print. */
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void
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smolpit::print() const
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{
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auto ff = std::cout.flags();
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std::cout << "isum=" << std::left << std::setw(3) << isummand << std::right << ": [";
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for (int i = 0; i < smolq.dimen(); i++)
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std::cout << std::setw(2) << (smolq.levels[isummand])[i] << ' ';
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std::cout << "] j=[";
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for (int i = 0; i < smolq.dimen(); i++)
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std::cout << std::setw(2) << jseq[i] << ' ';
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std::cout << std::showpos << std::fixed << std::setprecision(3)
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<< "] " << std::setw(4) << w << "*(";
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for (int i = 0; i < smolq.dimen()-1; i++)
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std::cout << std::setw(4) << p[i] << ' ';
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std::cout << std::setw(4) << p[smolq.dimen()-1] << ')' << std::endl;
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std::cout.flags(ff);
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}
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/* Here is the constructor of SmolyakQuadrature. We have to setup ‘levels’,
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‘levpoints’ and ‘cumevals’. We have to go through all d-dimensional
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sequences k, such that l≤|k|≤l+d−1 and all kᵢ are positive integers. This is
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equivalent to going through all k such that l−d≤|k|≤l−1 and all kᵢ are
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non-negative integers. This is equivalent to going through d+1 dimensional
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sequences (k,x) such that |(k,x)|=l−1 and x=0,…,d−1. The resulting sequence
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of positive integers is obtained by adding 1 to all kᵢ. */
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SmolyakQuadrature::SmolyakQuadrature(int d, int l, const OneDQuadrature &uq)
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: QuadratureImpl<smolpit>(d), level(l), uquad(uq)
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{
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// TODO: check l>1, l≥d
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// TODO: check l≥uquad.miLevel(), l≤uquad.maxLevel()
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int cum = 0;
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for (const auto &si : SymmetrySet(l-1, d+1))
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{
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if (si[d] <= d-1)
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{
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IntSequence lev(si, 0, d);
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lev.add(1);
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levels.push_back(lev);
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IntSequence levpts(d);
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for (int i = 0; i < d; i++)
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levpts[i] = uquad.numPoints(lev[i]);
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levpoints.push_back(levpts);
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cum += levpts.mult();
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cumevals.push_back(cum);
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}
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}
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}
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/* Here we return a number of evalutions of the quadrature for the given level.
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If the given level is the current one, we simply return the maximum
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cumulative number of evaluations. Otherwise we call costly
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calcNumEvaluations() method. */
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int
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SmolyakQuadrature::numEvals(int l) const
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{
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if (l != level)
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return calcNumEvaluations(l);
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else
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return cumevals[numSummands()-1];
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}
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/* This divides all the evaluations to ‘tn’ approximately equal groups, and
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returns the beginning of the specified group ‘ti’. The granularity of
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divisions are summands as listed by ‘levels’. */
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smolpit
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SmolyakQuadrature::begin(int ti, int tn, int l) const
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{
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// TODO: raise is level≠l
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if (ti == tn)
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return smolpit(*this, numSummands());
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int totevals = cumevals[numSummands()-1];
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int evals = (totevals*ti)/tn;
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unsigned int isum = 0;
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while (isum+1 < numSummands() && cumevals[isum+1] < evals)
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isum++;
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return smolpit(*this, isum);
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}
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/* This is the same in a structure as SmolyakQuadrature constructor. We have to
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go through all summands and calculate a number of evaluations in each
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summand. */
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int
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SmolyakQuadrature::calcNumEvaluations(int lev) const
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{
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int cum = 0;
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for (const auto &si : SymmetrySet(lev-1, dim+1))
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{
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if (si[dim] <= dim-1)
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{
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IntSequence lev(si, 0, dim);
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lev.add(1);
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IntSequence levpts(dim);
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for (int i = 0; i < dim; i++)
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levpts[i] = uquad.numPoints(lev[i]);
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cum += levpts.mult();
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}
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}
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return cum;
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}
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/* This returns a maximum level such that the number of evaluations is less
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than the given number. */
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void
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SmolyakQuadrature::designLevelForEvals(int max_evals, int &lev, int &evals) const
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{
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int last_evals;
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evals = 1;
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lev = 1;
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do
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{
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lev++;
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last_evals = evals;
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evals = calcNumEvaluations(lev);
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}
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while (lev < uquad.numLevels() && evals <= max_evals);
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lev--;
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evals = last_evals;
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}
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